/ 


Issued  June  11, 1912. 

U.  S.  DEPARTMENT  OF  AGRICULTURE, 

FOREST   SERVICE. 

HENRY  S.  GRAVES,  Forester. 


FOREST  PRODUCTS  LABORATORY  SERIES. 


EXPERIMENTS  WITH 

JACK  PINE  AND  HEMLOCK  FOR 

MECHANICAL  PULP. 


BY 


J.  H.  THICKENS,  .?snry 

Chemical  Engineer  in  Forest  Products. 


WASHINGTON: 

GOVERNMENT  'PRINTING  OFFICE. 
1912. 


Rwsest  £ef*Ic5*  W^S.^Ifi.cf  AgriooJture— jVlechanical  Pulp 


PLATE  I. 


FIG.  1  .—MOTOR  GENERATOR  SET  AND  SWITCHBOARD. 


FIG.  2. -GRINDER  AND  WET-MACHINE  ROOM. 


Issued  June  il, 

U.  S.  DEPARTMENT  OF  AGRICULTURE, 

FOREST    SERVICE. 

HENRY  S.  GRAVES,  Forester. 


FOREST  PRODUCTS  LABORATORY  SERIES. 


EXPERIMENTS  WITH 

JACK  PINE  AND  HEMLOCK  FOR 

MECHANICAL  PULP. 


BY 


J.  H.  THICKENS, 
// 

Chemical  Engineer  in  Forest  Products. 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE. 
1912. 


LETTER  OF  TRANSMITTAL 


UNITED  STATES  DEPARTMENT  OF  AGRICULTURE, 

FOREST  SERVICE, 
Washington,  D.  0.,  December  13,  1911. 

SIR:  I  have  the  honor  to  transmit  herewith  a  manuscript  entitled 
"  Experiments  with  Jack  Pine  and  Hemlock  for  Mechanical  Pulp," 
by  J.  H.  Thickens,  chemical  engineer  in  forest  products,  and  to 
recommend  its  publication. 

Respectfully,  HENRY  S.  GRAVES, 

Forester. 
Hon.  JAMES  WILSON, 

Secretary  of  Agriculture. 
2 


CONTENTS. 


Page. 

Need  of  a  substitute  for  spruce  pulp  wood 5 

Results  of  experiments 6 

Why  jack  pine  and  hemlock  have  not  been  used  for  pulp 7 

Equipment  used  in  the  experiments 8 

Electrical  equipment 8 

Pulp  machinery  and  auxiliary  equipment 8 

Methods  employed .* 10 

Qualitative  and  quantitative  tests 10 

Commercial  tests 10 

Treatment  of  the  wood  before  grinding 10 

Grinding 11 

Losses  in  grinding 12 

Fiber  study 12 

Calculation  of  results 12 

Comparison  of  yields 13 

Factors  which  influence  quality  and  production 15 

Speed  and  pressure 15 

Surface  of  stone 16 

Temperature 18 

Undetermined  factors 18 

Microscopic  comparison  of  experimental  pulps  and  commercial  standards 18 

Standard  pulps 18 

Jack  pine  pulp 20 

Hemlock  pulp 21 

Mixed  pulps 21 

Samples  of  paper  produced 22 

Summary  of  data 23 

3 


477631 


L  LUSTRATIONS. 


PLATES. 

Page. 
PLATE  I.  Fig.  1. — Motor  generator  set  and  switchboard.     Fig.  2. — Grinder  and 

wet-machine  room Frontispiece. 

II.  Fig.  1. — Natural  surface  of  stone  (jack  pine  run  No.  2).  Fig.  2. — Ten 
to  the  inch  solid,  straight-cut  burr  (hemlock  run  No.  0).  Fig.  3. — 
Eight  to  the  inch  solid,  spiral  burr  (hemlock  run  No.  43) 8 

III.  Fig.  1.— Three  to  the  inch  solid,  straight-cut  burr  (hemlock  run  No. 

46).  Fig.  2. — Three  to  the  inch  solid,  straight-cut  burr,  cut  over 
with  12  to  the  inch  solid,  spiral  burr  (hemlock  run  No.  51).  Fig. 
3. — Six  to  the  inch  diamond-point  burr  (jack  pine  run  No.  17-1) . .  8 

IV.  Fig.  1. — Spruce  sulphite  standard.     Fig.  2. — Spruce  ground  wood, 

No.  1  standard 16 

V.  Fig.   1. — Spruce  ground  wood,   No.   2  standard.    Fig.  2. — Spruce 

ground  wood,  No.  3  standard,  coarse  ground 16 

VI.  Fig.   1. — Spruce  ground  wood,   No.  4  standard,  medium  ground. 

Fig.  2. — Spruce  ground  wood,  No.  5  standard,  fine  ground 16 

VII.  Comparison  of  hemlock  pulps  ground  at  different  speeds.  Fig.  1. — 
100  revolutions  per  minute  (run  No.  35).  Fig.  2. — 150  revolutions 
per  minute  (run  No.  36).  Fig.  3. — 200  revolutions  per  minute 

(run  No.  37) 16 

VIII.  Comparison  of  jack  pine  pulps  ground  at  different  speeds.  Fig.  1. — 
152  revolutions  per  minute  (run  No.  19).  Fig.  2. — 205  revolu- 
tions per  minute  (run  No.  20-1) 16 

IX.  Fig.  1. — Jack  pine  ground  wood  (run  No.  14-1).     Fig.  2. — Jack  pine 

ground  wood  (run  No.  13-1) '. . '       16 

X.  Fig.  1. — Jack  pine  ground  wood  (run  No.  7-1).     Fig.  2. — Jack  pine 

ground  wood  (commercial  run  No.  24) :V        16 

XI.  Fig.  1. — Hemlock  ground  wood  (run  No.  41).     Fig.  2. — Hemlock 

ground  wood  (commercial  run  No.  14-1) 16 

XII.  Fig.  1. — Hemlock  ground  wood  (commercial  run  No.  8).     Fig.  2. — 

Hemlock  ground  wood  (run  No.  2) 16 

XIII.  Fig.  1. — Hemlock  ground  wood  (commercial  run  No.  30).     Fig.  2. — 

Hemlock  ground  wood  (commercial  run  No.  50).     (Used  in  accom- 
panying paper  sample) 16 

XIV.  Fig.  1. — Ground-wood  pulp,  one-third  spruce,  two-thirds  hemlock 

(run  No.  46a).     Fig.  2. — Ground-wood  pulp,  all  hemlock  (run  No. 

466).     Fig.  3. — Ground-wood  pulp,  all  spruce  (run  No.  46c) 16 

XV.  Mixed  ground-wood  pulps  (used  in  accompanying  paper  samples). 
Fig.  1. — One-third  spruce,  two- thirds  hemlock  (commercial  run 
No.  46a).  Fig.  2. — One-third  hemlock,  one-third  jack  pine,  one- 
third  spruce  (commercial  run  No.  51).  Fig.  3.— One-third  jack 
pine,  two-thirds  hemlock  (commercial  run  No.  52) 16 

TEXT   FIGURE. 

FIG.  1.  Portion  of  a  chart  from  a  recording  wattmeter,  showing  decreased  power 

consumption  after  removal  of  load  from  pocket  and  pocket  binding. . .         14 
4 


EXPERIMENTS  WITH  JACK  PINE  AND  HEMLOCK  FOR 
MECHANICAL  PULP. 


NEED  OF  A  SUBSTITUTE  FOB  SPRUCE  PULPWOOD. 

Few  well-established  industries  have  expanded  as  rapidly  as  has  the 
pulp  and  paper  industry.  In  less  than  a  decade  the  amount  of  raw 
material  used  annually  has  more  than  doubled.  During  1900 l 
there  were  consumed  in  the  United  States  1,986,310  cords  of  pulp- 
wood.  The  ground-wood  process  used  598,229  cords  of  domestic 
spruce,  120,820  cords  of  imported  spruce,  and  67,791  cords  of  other 
woods,  such  as  hemlock,  jack  pine,  poplar,  and  balsam,  or  a  total  of 
786,840  cords.  During  1909  2  the  amount  of  wood  used  in  all  proc- 
esses was  4,001,607  cords,  the  ground-wood  process  using  a  total  of 
1,246,121  cords,  which  consisted  of  806,282  cords  of  domestic  spruce, 
317,289  cords  of  imported  spruce,  and  122,550  cords  of  other  miscel- 
laneous woods. 

Thus  the  increase  in  the  total  amount  of  pulpwood  used  during  this 
period  was  101  per  cent,  while  the  amount  of  pulpwood  of  all  kinds 
used  for  ground  wood  increased  58J  per  cent.  The  domestic  spruce 
consumption  for  this  purpose  increased  35  per  cent  and  the  con- 
sumption of  miscellaneous  woods  80.5  per  cent.  But  the  largest 
increase  was  in  the  use  of  imported  spruce,  the  consumption  of  which 
increased  162  per  cent. 

The  price  of  spruce  has  increased  at  a  very  rapid  rate.  In  1900  the 
average  cost  of  spruce  used  in  all  processes  in  the  United  States  was 
$4.83  per  cord  for  domestic  spruce  and  $6.50  for  imported,  while  in 
1909  the  average  price  of  domestic  spruce  was  $9.32  and  of  imported 
$11.34  per  cord. 

This  increase  has  been  reflected  in  the  cost  of  ground-wood  pulp. 
The  manufacturing  cost  of  pulp,  as  determined  by  the  Tariff  Board,3 
increased  from  $10.84  per  ton  in  1900  to  $16.58  in  1909,  93  per  cent  of 
this  increase  being  accounted  for  by  the  greater  cost  of  the  wood  used. 
Manifestly,  therefore,  it  is  almost  essential,  if  the  ground-wood 

i  Twelfth  Census  of  the  United  States. 
a  "  Pulpwood  consumption,  1909,"  Bureau  of  the  Census. 

3  Report  by  the  Tariff  Board  relative  to  pulp  and  news  print  paper  industry,  Senate  Document  No.  31, 
Sixty-second  Congress,  first  session. 

5 


8  JACK  PINE  AND   HEMLOCK  FOR   MECHANICAL  PULP. 

industry  is  to  centime,  that  substitutes  be  found  for  spruce  pulp, 
especially  in  the  manufacture  of  news,  wrapping,  and  other  of  the 
cheaper  grades  of  paper.  To  determine  whether  there  are  not  other 
domestic  species  which  will  produce  a  commercial  grade  of  ground 
wood  suitable  for  the  purpose,  etc.,  the  Forest  Service,  in  cooperation 
with  the  American  Pulp  and  Paper  Association,  began  an  extensive 
series  of  tests  on  several  of  the  woods  which  occur  in  large  quantities 
in  the  United  States,  particularly  in  the  Lake  States.  The  woods 
which  have  been  tried  up  to  the  present  are  hemlock  and  jack  pine, 
together  with  a  small  amount  of  spruce,  for  the  purpose  of  comparison. 
The  experiments  were  conducted  at  Wausau,  Wis.,  under  the 
general  supervision  of  the  director  and  assistant  director  of  the 
Forest  Products  Laboratory,  and  an  advisory  committee  of  the 
American  Pulp  and  Paper  Association,  composed  of  Messrs.  G.  F. 
Steele,  chairman  Nekoosa-Edwards- Paper  Co.;  W.  G.  McNaughton, 
secretary  Nekoosa-Ed wards  Paper  Co. ;  D.  C.  Everest,  Marathon 
Paper  Mills  Co.;  W.  L.  Edmonds,  Wausau  Paper  Mills  Co.;  A.  M. 
Pride,  Tomahawk  Paper  Co. ;  and  Wm.  Eibel,  Rhinelander  Paper  Co. 

RESULTS  OF  EXPERIMENTS. 

Not  only  have  very  promising  sheets  of  pulp  been  obtained  from 
both  the  hemlock  and  jack  pine,  but  paper  has  been  made  from 
them  on  commercial  machines,  operating  at  high  speed,  and  under 
all  other  conditions  of  actual  commercial  practice,  which  has  the 
strength,  finish,  and  appearance  of  standard  news  paper.  The 
production  per  grinder,  the  horsepower  consumption  per  ton,  and 
the  yield  per  cord  approximate  the  averages  which  obtain  in  the 
grinding  of  spruce.  Again,  pulps  composed  of  mixtures  of  hemlock, 
spruce,  and  jack  pine  in  different  proportions  have  been  obtained, 
which  compare  very  favorably  with  the  ordinary  spruce  ground  wood. 

Hemlock  ground  wood  has  a  decided  reddish  tinge,  though  this  is 
not  very  noticeable,  even  in  an  all-hemlock  sheet  of  news  paper. 
Jack  pine  pulp  is  also  slightly  off  in  color,  but  is  not  nearly  as  dark 
as  hemlock  pulp.  Careful  study  by  experts  should  make  it  possible 
to  bring  the  color  of  the  paper  produced  from  these  pulps  more 
nearly  to  the  usual  white.  As  it  is,  the  sheets  of  news  paper  which 
have  been  secured  are  only  slightly  off  color,  though  they  are  the 
result  in  each  case  of  but  a  single  attempt  to  secure  the  standard 
degree  of  whiteness. 

Since  the  experiments  on  hemlock  have  brought  out  a  number  of 
points  in  favor  of  the  grinding  of  that  wood,  two  paper-mill  com- 
panies have  signified  their  intention  of  using  it  in  their  cheaper  grades 
of  paper.  One  of  these  mills  has  already  begun  to  do  so,  and  is  well 
satisfied  with  the  pulp  obtained. 


JACK    PINE   AND    HEMLOCK   FOR    MECHANICAL   PULP.  7 

WHY  JACK  PINE  AND  HEMLOCK  HAVE  NOT  FEEN  USED. 

There  is  much  doubt  as  to  exactly  why  the  pulp  industry  has 
neglected  to  use  hemlock  and  jack  pine  for  the  cheaper  grades  of 
paper.  It  seems  to  be  the  general  impression  that  hemlock  grinds 
so  fine  and  short  that  there  is  a  great  loss  in  conversion.  It  has  been 
said  that  the  yield  obtained  is  in  many  instances  only  three-fifths  of 
that  from  an  equal  amount  of  spruce.  This  loss  in  grinding  hemlock 
has  not  been  in  evidence  during  the  tests. 

The  pitch  in  jack  pine  is  undoubtedly  responsible  for  the  lack  of 
attention  paid  to  that  wood.  This,  however,  can  be  removed  by 
steaming  or  soaking,  and  such  treatments  will  be  taken  up  in  future 
experiments. 

In  all  the  experiments  the  yields  secured  from  the  different  woods 
were  in  direct  proportion  to  their  bone-dry  weight  per  cubic  foot. 
It  is  therefore  to  be  expected  that  the  yields  from  jack  pine  and 
hemlock  will  be  less  per  unit  of  volume  than  those  from  spruce,  since 
the  two  first  woods  are  considerably  lighter  in  weight.  On  the  basis 
of  weight,  however,  there  appears  to  be  relatively  little  more  loss  in 
converting  hemlock  or  jack  pine  into  pulp  than  in  converting  spruce. 

The  fiber  obtained  from  the  ground  hemlock  and  jack  pine  has 
been  considered  unsatisfactory  on  account  of  its  shortness.  Yet  it 
has  been  found  long  enough  for  use  in  cheap  papers. . 

One  who  is  accustomed  to  handling  spruce  ground  wood  will  not 
be  favorably  impressed  with  the  appearance  of  either  hemlock  or 
jack  pine  pulp.  This  is  particularly  true  of  the  hemlock  sheet. 
Both  pulps  are  somewhat  softer  in  texture  than  spruce,  and,  alto- 
gether, are  not  as  pleasing  in  appearance  as  the  present  commercial 
product. 

Another  point  which  may  account  for  the  lack  of  attention  paid 
to  hemlock  and  jack  pine  is  the  care  which  must  be  exercised  in 
grinding  them.  It  is  possible  to  obtain  a  grade  of  pulp  from  spruce 
which  is  suitable  for  most  purposes  without  using  a  great  deal  of 
care  in  the  preparation  of  the  surface  of  the  pulp  stones.  In  the 
grinding  of  jack  pine  and  hemlock,  especially  hemlock,  on  the  other 
hand,  great  care  must  be  exercised  in  bringing  the  stone  to  the  correct 
degree  of  sharpness,  since  these  woods  will  grind  to  powder  if  the 
surface  is  as  sharp  as  the  one  ordinarily  employed  in  grinding  spruce. 

Yet  notwithstanding  certain  shortcomings  the  fact  remains  that 
it  is  possible  to  obtain  hemlock  and  jack  pine  pulps  commercially 
which  are  suitable  for  the  cheaper  grades  of  paper. 


8  JACK   PINE   AND   HEMLOCK   FOR    MECHANICAL   PULP. 

EQUIPMENT  USED  IN  THE  EXPERIMENTS. 
ELECTRICAL    EQUIPMENT. 

To  study  accurately  the  fundamental  variables  of  grinding  it  was 
necessary  to  install  an  elaborate  electrical  drive  and  apparatus  for 
control  and  manipulation.  There  has  also  been  provided  a  system 
of  recording  instruments  for  the  determination  of  speed,  pressure, 
and  load  fluctuation.  The  electrical  apparatus  consists  of  a  motor- 
generator  set  and  a  direct-current  variable-speed  motor.  The 
variable-speed  motor,  direct  connected  to  the  pulp  grinder,  is  rated 
at  225  horsepower  at  100  revolutions  per  minute  and  500  horsepower 
at  300  revolutions  per  minute,  with  a  50  per  cent  overload  capacity 
at  all  speeds.  However,  it  is  possible  to  obtain  about  25  per  cent 
more  capacity  than  the  rating.  Variation  in  speed  is  obtained  by 
variation  of  voltage  applied  to  the  motor  armature,  and  by  means 
of  a  rheostat  in  the  field  circuit  of  the  generator  it  is  possible  to 
maintain  this  voltage  at  any  point  desired,  thus  giving  a  very  con- 
stant speed. 

The  efficiency  of  the  grinder  motor  has  been  determined  for  all 
values  of  speed  and  load  throughout  the  range  of  usage.  Conse- 
quently, the  power  applied  to  the  grinder  at  any  value  of  peripheral 
speed  or  at  any  pressure  on  the  cylinders  can  be  calculated. 

Individual  motor  drives  have  also  been  installed  for  the  various 
other  pieces  of  pulp-making  machinery  and  their  auxiliary  apparatus. 
The  machines  for  wood  preparation  and  the  wet-machine  vacuum 
pump  are  the  only  ones  which  are  not  direct  connected  to  indi- 
vidual motors.  In  several  cases  variable-speed  motors  have  been 
installed  to  permit  adjustment  of  speed  to  the  most  effective  value. 

PULP   MACHINERY    AND    AUXILIARY   EQUIPMENT. 

The  pulp-making  machinery,  machines  for  wood  preparation,  and 
the  auxiliary  pieces  of  apparatus  are  all  of  standard  commercial 
types  and  were  loaned  by  the  following  manufacturers  or  others 
interested  in  the  work  of  the  laboratory: 

Grinder Friction  Pulley  and  Machine  Works. 

Wet  machine Improved  Paper  Machinery  Co. 

Flat  screen Harmon  Machine  Co. 

Ruth  centrifugal  screen H.  L.  Orrman  &  Co. 

5  by  8  inch  triplex  pump Goulds  Manufacturing  Co. 

4  by  6  inch  triplex  pump Do. 

5-inch  centrifugal  pump Do . 

4-inch  centrifugal  pump Do. 

Storage  tank Valley  Iron  Works. 

Barker. . .     .'..... Green  Bay  Foundry  and  Machine  Works. 


Forest  Service,  U.  S.  Dept  of  Agriculture— Mechanical  Pulp. 


PLATE  II. 


FIG.  1.— NATURAL  SURFACE  OF  STONE.    (JACK  PINE  RUN  No.  2.) 


FIG.  2.— TEN  TO  THE  INCH  SOLID;  STRAIGHT-CUT  BURR.    (HEMLOCK  RUN  No.  0.) 


FIG.  3.— EIGHT  TO  THE  INCH  SOLID;  SPIRAL  BURR.    (HEMLOCK  RUN  No.  43.; 


Forest  Service,  U.  S.  Dept.  of  Agriculture— Mechanical  Pulp.  PLATE    III. 


FIG.  1.— THREE  TO  THE  INCH  SOLID;  STRAIGHT-CUT  BURR.    (HEMLOCK  RUN  No.  46.) 


FIG.  2.— THREE  TO  THE  INCH  SOLID;  STRAIGHT-CUT  BURR.    CUT  OVER  WITH  TWELVE 
TO  THE  INCH  SOLID;  SPIRAL  BURR.    (HEMLOCK  RUN  NO.  51.) 


FIG.  3.— Six  TO  THE  INCH  DIAMOND  POINT  BURR.    (JACK  PINE  RUN  No.  17-1.) 


JACK   PINE  AND   HEMLOCK  FOR  MECHANICAL  PULP.  9 

Swing  cut-off  saw American  Pulp  and  Paper  Association. 

3-ton  scale Paper  (Inc.). 

2  Ash  ton  relief  valves Do. 

1  pulp  truck W.  A.  Lounsberry  &  Co. 

1  wood  truck Do. 

1  54  by  27  inch  pulp  stone Manufacturers'  Paper  Co. 

12  42-inch  screen  plates Union  Screen  Plate  Co. 

1  wet-machine  felt Albany  Felt  Co. 

1  wet-machine  felt Appleton  Woolen  Mills. 

1  set  barker  knives Dowd  Knife  Works. 

1  set  sectional  and  solid  burrs.  .Ticonderoga  Machine  Works. 

Plate  I  shows  a  portion  of  the  pulp-making  equipment.  The 
grinder  (PL  I,  fig.  2)  has  three  pockets,  the  cylinders  are  14  inches 
in  diameter,  and  it  is  designed  for  a  54  by  27  inch  pulp  stone.  Each 
of  the  grinder  cylinders  is  equipped  with  a  pressure  gauge,  and  the 
pressure  line  between  the  triplex  pumps  and  the  grinder  is  provided 
with  Ashton  relief  valves,  which  make  it  possible  to  obtain  very 
uniform  pressures  up  to  100  pounds  per  square  inch. 

A  recording  thermometer  gives  a  record  of  the  temperature  in  the 
grinder  pit.  From  the  grinder  pit  the  pulp  is  passed  through  a 
mechanically  agitated  sliver  screen,  then  pumped  to  a  storage  tank 
by  means  of  a  6-inch  centrifugal  pump,  and  from  there  pumped  to  a 
centrifugal  screen.  A  variable-speed  motor  direct  connected  to  the 
screen  makes  it  possible  to  obtain  speeds  of  rotation  from  400  to  600 
revolutions  per  minute.  Throughout  the  tests,  however,  the  speed 
was  maintained  at  500  revolutions  per  minute.  The  plate  in  the 
centrifugal  screen  is  perforated  with  holes  0.065  inch  in  diameter. 
The  tailings  from  it  are  led  by  gravity  to  a  12-plate  horizontal  dia- 
phragm screen,  the  plates  of  which  are  the  Union  Screen  Plate  Go's, 
type  B,  cut  with  0.012-inch  slots. 

The  good  pulps  from  the  centrifugal  and  the  plate  screens  are 
united  in  the  vat  of  the  wet  machine,  which  is  direct  connected  to  a 
variable-speed  motor  giving  felt  speeds  ranging  from  75  to  115  feet 
per  minute.  The  wet  machine  is  provided  with  a  small  triplex  pump 
by  which  the  cylinders  connected  to  the  press  rolls  are  operated,  the 
dryness  of  the  pulp  being  determined  by  the  pressure  applied  to  the 
cylinders.  A  vacuum  of  from  10  to  15  inches,  produced  by  a  rotary 
suction  pump,  is  maintained  on  the  felt,  and  this,  too,  assists  in 
obtaining  the  desired  dryness  of  the  pulp.  The  white  water  from 
the  wet-machine  vat  is  pumped  back  to  the  grinder  sliver  screen  by  a 
4-inch  centrifugal  pump.  White  water  from  the  felts  is  run  directly 
to  the  sewer,  as  is  also  the  white  water  from  the  felt  suction.  Plate 
I,  figure  2,  gives  an  idea  of  the  general  arrangement  of  the  pulp- 
making  machinery.  A  40-inch  swing  cut-off  saw  and  a  Green  Bay 
wood  barker  are  used  to  prepare  the  wood. 


10  JACK   PINE   AND   HEMLOCK  FOR   MECHANICAL  PULP. 

METHODS  EMPLOYED. 
QUALITATIVE    AND    QUANTITATIVE    TESTS. 

In  order  to  cover  the  field  in  a  reasonable  length  of  time,  short  tests 
ranging  up  to  two  hours  in  length  were  run.  In  these  tests  no  attempt 
was  made  to  cover  every  point,  the  object  being  to  touch  only  such 
as  were  thought  to  have  a  marked  effect  on  the  quality  of  the  product. 
The  surface  of  the  stone,  the  pressure  on  the  grinder  cylinder,  and 
the  peripheral  speed  of  the  stone  were  the  variables  which  received 
most  attention.  No  especial  attention  was  given  to  economic  con- 
siderations. 

Tests  were  made  with  pressures  of  from  20  to  75  pounds  per  square 
inch  on  the  cylinder,  corresponding  to  from  8.2  to  30.8  pounds  per 
square  inch  of  pocket  area.  The  speed  of  rotation  of  the  stone  was 
varied  from  84  to  225  revolutions  per  minute,  corresponding  to  a 
range  in  peripheral  speed  of  from  1,173  to  3,150  feet  per  minute. 

In  studying  the  effect  of  the  surface  condition  of  the  stone  it  was 
necessary  to  utilize  burrs  of  many  different  types  and  designs. 
These  ranged  in  fineness  of  cut  from  12  to  the  inch  to  3  to  the  inch. 
The  style  of  cut  differed  also,  spiral  cut,  diamond  points,  and  straight 
cut  being  employed.  The  power  applied  to  the  grinder  ranged  from 
87.3  to  520  horsepower,  while  the  rate  of  production  of  bone-dry 
pulp  varied  from  1  ton  to  7.3  tons  in  24  hours.  It  should  be  under- 
stood that  neither  the  two  minimum  nor  the  two  maximum  values 
were  necessarily  obtained  from  the  same  test.  When  the  power 
applied  to  the  grinder  was  87.3  horsepower,  for  instance,  it  does  not 
necessarily  follow  that  the  production  was  1  ton  per  day.  The  horse- 
power consumption  per  ton  under  the  given  conditions  was  found  to 
vary  from  68.3  to  196  in  24  hours. 

The  samples  of  pulp  obtained  during  the  qualitative  and  quanti- 
tative tests  were  examined  and  commented  upon  by  members  of  the 
advisory  committee  of  the  American  Pulp  and  Paper  Association,  and 
those  runs  considered  most  promising  were  duplicated  later  in 
commercial  tests. 

COMMERCIAL    TESTS. 
TREATMENT   OF  THE    WOOD    BEFORE    GRINDING. 

All  of  the  wood  used  in  the  tests  was  cut  either  in  Wisconsin  or 
Michigan  and  was  representative  of  the  species.  In  some  cases  the 
wood  was  secured  directly  from  the  forest,  while  in  others  it  was 
shipped  to  the  laboratory  from  near-by  mills.  Upon  arrival  at  the 
laboratory  the  logs  were  closely  piled  on  skids.  An  attempt  was  made 
to  keep  the  material  green  by  painting  the  ends  with  paraffin,  but  this 
proved  unsatisfactory,  because  the  paraffin  peeled  off.  The  wood 
tested  was  taken  directly  from  the  piles  for  all  tests  up  to  and  includ- 


JACK   PINE  AND   HEMLOCK  FOB   MECHANICAL  PULP.  11 

ing  run  No.  52  of  the  hemlock  series,  with  the  exception  of  runs  Nos. 
49,  50,  and  51,  the  wood  for  which  was  soaked  in  the  pond  for  approxi- 
mately two  months  before  being  used.  The  only  jack  pine  soaked 
was  that  used  in  the  commercial  test  on  seasoned  wood  of  that  spe- 
cies— run  14.  The  jack  pine  and  spruce  used  in  tests  on  mixed  pulps 
were  in  all  cases  dry  before  grinding.  The  wood  for  the  tests  was 
prepared  approximately  2  cords  at  a  time,  sawed  into  2-foot  lengths, 
barked,  weighed,  and  piled  up  for  the  grinding  process. 

To  determine  accurately  the  yield,  the  bone-dry  weight  per  cubic 
foot  of  wood,  as  well  as  the  percentage  of  moisture  present,  was 
determined  in  each  commercial  test.  All  weighings  were  made  in 
500  or  1,000  pound  lots,  and  the  wood  was  used  as  soon  as  ground. 

No  attempt  was  made  to  remove  knots  or  punky  portions  of  the 
wood.  In  fact,  all  of  the  tests  were  carried  on  in  accordance  with 
the  usual  commercial  practice. 


GRINDING. 


Before  commencing  the  grinding  tests  an  impression  of  the  surface 
of  the  stone  which  had  been  selected  was  taken  by  means  of  a  piece 
of  carbon  paper  and  a  sheet  of  coated  paper.  This  impression  was 
later  photographed,  as  shown  in  Plates  II  and  III.  In  these  the 
black  dots  represent  projecting  points  and  the  white  portions 
between  them  depressions  in  the  stone.  The  surface  shown  in  Plate 
III,  figure  2,  is  particularly  interesting,  since  it  is  the  result  of  dressing 
with  two  different  kinds  of  burrs. 

Before  starting  the  tests  the  recording  thermometer  and  all  of  the 
other  recording  instruments  were  placed  in  operation.  The  pockets 
of  the  grinder  were  filled,  the  pressure  adjusted  to  the  proper  value, 
and  the  grinder  started. 

For  the  purpose  of  check  and  control,  regular  readings  were  taken 
of  the  various  switchboard  instruments,  the  indicating  tachometer, 
the  pressure  gauges,  and  the  recording  thermometer.  On  short  tests 
up  to  2  hours  in  length  these  readings  were  recorded  at  5-minute 
intervals,  but  on  longer  tests  the  interval  was  increased  to  15  minutes. 
The  speed,  pressure,  and  other  variables  were  maintained  as  nearly 
constant  as  possible.  For  instance,  when  one  of  the  grinder  pistons 
was  raised  the  speed  was  brought  back  to  the  desired  value  by 
manipulation  of  the  rheostat  controlling  the  motor  armature  voltage. 

During  the  qualitative  and  quantitative  tests  the  pulp  stone  did  not 
have  an  opportunity  to  heat  up,  and,  in  consequence,  some  of  the 
data  on  power  consumption  and  production  may  be  more  or  less 
questionable.  In  the  commercial  tests,  however,  all  of  which  were 
made  under  the  hot-grinding  process,  the  stone  was  brought  up  to  a 
high  temperature,  which  was  maintained  throughout  the  run;  con- 
sequently these  more  nearly  approximate  commercial  conditions. 


12  JACK   PINE   AND   HEMLOCK   FOR    MECHANICAL   PULP. 


LOSSES  IN   GRINDING. 


To  determine  approximately  the  losses  occurring  in  the  conversion 
of  wood  to  pulp,  the  bone-dry  weight  of  screenings  obtained  from  a 
known  amount  of  bone-dry  wood  was  determined.  The  loss  in  the 
white  water  was  then  taken  as  the  difference  between  the  bone-dry 
weight  of  the  wood  ground  and  the  bone-dry  weight  of  the  pulp 
secured  plus  the  screenings. 

FIBER   STUDY. 

During  each  test  the  character  of  fiber  obtained  was  examined  by 
means  of  an  apparatus  for  microscopic  study.  This  consists  of  an 
ordinary  stereopticon  provided  with  a  specially  constructed  carrier 
for  microscopic  slides.  Samples  of  wet  pulp  were  taken  from  the 
wet-machine  vat  and  slides  were  made  by  first  removing  the  water 
by  drying,  then  staining  with  Bismarck  brown,  and  moistening  with 
glycerine.  The  mixture  of  glycerine  and  fiber  was  teased  out  to 
cover  the  area  of  an  ordinary  microscopic  cover  glass,  which  was 
placed  over  the  mixture.  Evaporation  or  leakage  was  prevented  by 
means  of  a  thin  strip  of  shellac  around  the  edge  of  the  cover  glass. 

With  this  apparatus  it  was  also  possible  to  compare  different 
samples  of  pulp  with  the  commercial  standards  used,  the  latter  being 
selected  from  a  large  number  of  samples  submitted  by  American 
manufacturers  of  ground- wood  pulp. 

CALCULATION  OF  RESULTS. 

To  give  a  clear  understanding  of  the  method  employed  in  calcu- 
lating the  various  items  in  connection  with  a  test,  all  the  calculations 
for  a  representative  run,  No.  50,  Table  4,  are  given  here.  Consid- 
erable data  taken  during  the  tests  have  been  eliminated  from  the 
compilation,  since  they  have  no  direct  bearing  on  the  study. 

The  test  mentioned  required  3.42  hours  to  complete,  and  during 
that  time  3,388  pounds  of  hemlock  wood  were  ground.  For  com- 
parison all  of  the  figures  on  weight  of  wood  were  brought  to  a 
bone-dry  basis.  The  bone-dry  weight  of  wood  was  secured  by 
drying  a  known  volume  of  wood  to  constant  weight  and  calculating 
the  weight  per  cubic  foot.  By  calculating  the  bone-dry  weight  of  a 
log  of  measured  volume  and  subtracting  this  amount  from  the  actual 
weight  of  the  log,  the'  moisture  content  of  the  wood  was  determined. 
The  bone-dry  weight  of  this  wood,  per  cubic  foot,  was  24.84  pounds, 
and  the  moisture  content  was  46.5  per  cent;  consequently  the  amount 
of  bone-dry  wood  ground  was  53.5  per  cent  of  3,388,  or  1,810  pounds. 
This  is  equivalent  to  72.9  cubic  feet  of  solid  wood  ground  during  the 


JACK    PINE   AND   HEMLOCK   FOR   MECHANICAL  PULP.  13 

given  period;  or,  in  other  words,  the  grinding  was  carried  on  at  the 
rate  of  512  cubic  feet  of  solid  wood  in  24  hours. 

The  amount  of  wet  pulp  obtained  during  the  test  was  3,795  pounds, 
and  this  upon  analysis  was  found  to  have  a  moisture  content  of  60.22 
per  cent.  Consequently,  1,507  pounds  of  bone-dry  pulp  were 
obtained  during  the  period  of  test,  corresponding  to  a  production  of 

or  5-3  tons  *n  24  hours.     To  grind  the  wood  and  pro- 


duce  this  pulp  it  was  necessary  to  apply  to  the  grinder  motor  power 
which  averaged  338  kilowatts.  This  value  was  obtained  by  dividing 
the  total  number  of  kilowatt  hours  used,  as  given  by  a  watt-hour 
meter,  by  the  length  of  the  test  in  hours.  Figure  1  shows  a  section  of 
a  wattmeter  record  obtained  during  this  test,  and  illustrates  how  the 
power  used  by  the  grinder  varied  upon  the  removal  of  the  load  from 
one  of  the  grinder  pockets.  The  entire  recording  wattmeter  curve 
was  averaged  by  means  of  a  planimeter,  in  order  to  check  the  value 
of  power  consumed  as  given  by  the  watt-hour  meter. 

By  using  curves  which  show  the  losses  in  the  motor  it  was  found 
that  15.3  kilowatts  were  required  to  supply  the  heat  losses  in  the 
grinder-motor  armature  and  7.1  kilowatts  to  supply  the  stray  power 
losses,  making  a  total  of  22.4  kilowatts  lost  in  converting  the  power 
from  electrical  to  mechanical.  This  amount  subtracted  from  338 
kilowatts  gives  315.6  kilowatts  which  were  furnished  to  the  grinder 
pulpstone,  and  315.6  divided  by  0.746  1  gives  the  value  of  422J  horse- 
power applied  to  the  grinder.  In  order,  then,  to  obtain  5.3  tons  of 
bone-dry  pulp  in  24  hours  it  was  necessary  to  apply  to  the  grinder 
over  that  period  422  J  horsepower,  or  the  horsepower  consumption 
per  ton  was  422J  divided  by  5.3,  or  79.7  horsepower  per  ton  in  24 
hours. 

The  yield  from  100  cubic  feet  of  solid  wood  was  obtained  by  dividing 
the  amount  of  pulp  produced  during  24  hours,  5.3  tons  or  10,600 
pounds,  by  the  number  of  hundreds  of  cubic  feet  of  wood  ground  in 
24  hours,  viz,  5.12.  The  result  is  2,070  pounds. 

The  average  temperature  of  grinding  was  determined  by  reading 
the  recording  thermometer  every  five  minutes,  adding  these  values, 
and  dividing  by  the  total  number  of  readings. 

COMPARISON   OF   YIELDS. 

Much  importance  is  attached  to  the  amount  of  pulp  obtained 
from  a  cord  of  wood,  because  this  represents  the  efficiency  of  con- 
version. Commercial  practice  in  the  manufacture  of  spruce  ground 
wood  requires  a  yield  of  approximately  2,300  pounds  per  cord  of 

i  A  horsepower  is  equivalent  to  0.-746  kilowatt. 


14 


JACK   PINE    AND    HEMLOCK   FOR    MECHANICAL   PULP, 


rossed  wood,  or  1,800  pounds  per  cord  of  rough  wood.     The  average 
yields  which  have  been  obtained  for  hemlock  and  jack  pine,  together 


KILOWATTS. 


FIG.  1. — Portion  of  chart  from  recording  wattmeter,  showing  decreased  power  consumption  after  removal 
of  load  frojuti  pocket  and  pocket  binding. 

with  those  obtained  for  two  different  shipments  of  spruce,  are  given 
in  Table  1. 


JACK    PINE   AND    HEMLOCK    FOR    MECHANICAL   PULP. 
TABLE  1. — Average  yields  from  spruce,  hemlock,  and  jack  pine. 


15 


Species. 

Weight  per 
100  cu.  ft. 
bone-dry. 

Yield  per 
100  cu.  ft. 
of  solid 
wood. 

Efficiency 
of 
conversion. 

Spruce 

Pounds. 

2,840 

Pounds. 
2  480 

Per  cent. 
87  3 

Do  

2,270 

2,000 

88  2 

Hemlock 

2,480 

2  100 

84  8 

Jack  pine 

2  540 

2  200 

86  7 

One  hundred  cubic  feet  of  solid  wood  was  selected  as  the  basis  of 
yield,  since  it  eliminates  the  variable  loss  in  barking,  and  represents 
fairly  well  the  amount  of  solid  wood  in  a  rossed  cord.  The  yield,  as 
will  be  seen,  is  directly  proportional  to  the  bone-dry  weight  of  the 
wood.  The  loss  in  conversion  has  been  found  to  range  between  12 
and  15  per  cent  of  the  original  weight  of  the  bone-dry  wood.  Ap- 
proximately 6  per  cent  can  be  accounted  for  in  the  white  water  and  1 
per  cent  in  screenings.  The  manner  in  which  the  remaining  losses 
occur  has  not  been  determined,  but  will  be  studied  in  future  tests. 

The  storage  capacity  for  white  water  in  the  laboratory  was  very 
limited,  and  this  may  to  some  extent  account  for  the  low  yields. 
The  continuous  use  of  the  white  water  and  the  use  of  save-alls  would 
undoubtedly  tend  to  increase  the  yields  and  result  in  saving  a  great 
deal  of  fine  pulp. 

The  loss  in  barking  jack  pine  and  hemlock,  so  far  as  has  been 
determined  up  to  the  present  time,  is  practically  the  same  as  the  loss 
in  the  barking  of  spruce.  There  are  a  great  many  knots  in  both 
hemlock  and  jack  pine,  and  it  is  possible  that  this  may  cause  a  some- 
what greater  loss  in  barking  these  species.  However,  on  account  of 
the  small  amounts  of  the  various  woods  used,  no  reliable  data  on  loss 
were  obtained. 

FACTORS   WHICH  INFLUENCE    QUALITY   AND   PRODUCTION. 
SPEED    AND    PRESSURE. 

The  effect  of  speed  on  the  quality  of  pulp  can  best  be  illustrated 
by  the  magnified  fibers  shown  in  Plates  VII  and  VIII.  In  grinding 
these  pulps  the  pressure  and  surface  of  the  stone  were  maintained 
constant,  and  the  speeds  were,  respectively,  100,  150,  and  200  revolu- 
tions per  minute  for  the  hemlock,  and  152  and  205  revolutions  for 
the  jack  pine.  There  is  little  difference  in  the  fibers  ground  under 
these  different  conditions  of  speed;  especially  those  run  at  150  and 
200  revolutions  per  minute.  Speed  probably  has  very  little  effect 
on  the  quality  of  pulp.  With  satisfactory  pressure  and  curface  of 
stone,  it  is  possible  to  obtain  good  grades  of  pulp  at  any  speeds  within 
reasonable  limits.  Commercially,  it  is  practically  impossible  to  main- 


16  JACK   PINE   AND   HEMLOCK   FOR    MECHANICAL   PULP. 

tain  the  speed  constant  at  all  times.  When  the  pressure  on  a  pocket 
is  removed  the  speed  is  bound  to  rise  considerably,  especially  when 
the  water  wheels  or  turbines  are  operated  without  a  governor. 

When  hemlock  wood  was  ground  at  low  speed  and  low  pressure 
it  was  impossible  to  obtain  anything  more  than  a  powder.  Also  when 
this  wood  was  ground  at  low  pressure  and  high  speed  the  product  was 
extremely  short,  but  the  pressures  at  which  these  results  were  obtained 
are  considerably  lower  than  those  ordinarily  employed  commercially, 
and  the  results  have  little  significance.  If  the  stone  is  what  is  ordi- 
narily called  sharp,  it  is  necessary  to  use  a  lower  pressure,  and  when 
dull,  a  higher  one,  but  it  is  impossible  to  obtain  the  same  quality  of 
pulp  under  both  conditions.  Speed  and  pressure  affect  quantity 
rather  than  quality,  and  by  the  proper  adjustment  of  both  the  maxi- 
mum efficiency  of  grinding  is  attained.  If  a  certain  speed  is  selected 
there  must  be  a  corresponding  pressure  which  will  yield  the  greatest 
amount  of  pulp  in  24  hours  with  the  least  consumption  of  power. 

By  the  term  " constant  pressure/'  wherever  used  in  this  report,  is 
meant  constant  pressure  on  the  grinder  cylinders.  The  pressure  per 
square  inch  of  wood  in  contact  with  the  grinding  surface  varies  con- 
siderably, chiefly  with  the  size  of  wood  ground  and  the  area  of  the 
pocket.  Again,  the  length  of  the  wood  is  not  at  all  a  constant  quantity, 
and  this,  too,  can  only  result  in  a  variable  pressure  per  square  inch  of 
wood.  The  pressure  of  the  wood  on  the  stone  varies  throughout 
certain  limits  with  any  pressure  on  the  grinder  cylinder,  and  the 
ranges  of  pressure  of  the  wood  on  the  stone  are  raised  or  lowered  by 
raising  or  lowering  the  cylinder  pressure.  This  pressure  variation, 
however,  can  hardly  be  controlled  commercially,  and  therefore  has 
not  been  considered  in  the  test's  discussed  in  this  report.  There  is 
also  more  or  less  pressure  variation  due  to  binding  of  wood  in  the 
pockets,  and  this,  too,  is  difficult,  if  not  impossible,  to  control. 
Figure  1  shows  a  measure  of  the  power  applied  to  the  grinder.  The 
effect  of  pocket  binding  and  the  withdrawal  of  pressure  from  one  of 
the  pockets  will  be  noted.  At  one  end  of  this  chart  the  power  con- 
sumed is  approximately  360  kilowatts,  falling  off  gradually  to  280 
kilowatts,  due  to  pocket  binding.  After  raising  the  pistons  and  read- 
justing the  wood  in  the  different  pockets,  the  power  to  the  grinder 
motor  had  to  be  increased  to  350  kilowatts  on  account  of  the  added 
load  produced  by  eliminating  the  pocket  binding. 

SURFACE    OF    STONE. 

The  most  efficient  grinding  condition  is  one  where  there  is  a  maxi- 
mum amount  of  grinding  surface,  and  still  a  sufficient  amount  of 
depression  in  the  stone  to  allow  for  the  carrying  away  of  the  ground 
wood,  or,  as  this  is  commonly  called,  for  the  clearing  of  the  stone. 


Forest  Service,  U.  S.  Dept.  of  Agriculture — Mechanical  Pulp. 


PLATE  IV. 


FIG.  1. -SPRUCE  SULPHITE  STANDARD. 


'-•.^^m^^stm 


FIG.  2.— SPRUCE  GROUND  WOOD,  No.  1  STANDARD. 


Forest  Service,  U.  S.  Dept.  of  Agriculture — Mechanical  Pulp. 


PLATE  V. 


.»  :.  \ 


FIQ.  1.— SPRUCE  GROUND  WOOD,  No.  2  STANDARD. 


FIG.  2.— SPRUCE  GROUND  WOOD,  No.  3  STANDARD,  COARSE  GROUND. 


Forest  Service,  U.  S.  Dept.  of  Agriculture — Mechanical  Pulp. 


PLATE  VI. 


FIG.  1.— SPRUCE  GROUND  WOOD,  No.  4  STANDARD,  MEDIUM  GROUND. 


m 


FIG.  2.— SPRUCE  GROUND  WOOD,  No.-  5  STANDARD,  FINE  GROUND. 


Forest  Service,  U.  S.  Dept.  of  Agriculture- Mechanical  Pulp. 


PLATE  VII. 


FIG.  1.-100  R.  P.  M.    (RUN  No.  35.) 


FIG.  2.— 150  R.  P.  M.    (RUN  No.  36.) 


-    «*.  •          • ,  - "- 


FlQ.  3.-200  R.  P.  M.    (RUN  No.  37.) 
COMPARISON    OF    HEMLOCK    PULPS   GROUND  AT   DIFFERENT    SPEEDS. 


Forest  Service,  U.  S   Dept.  of  Agriculture — Mechanical  Pulp. 


PLATE  VIII. 


fflnBi  3IP4, 


^XM^^mMm 


FIG.  1.-152  R.  P.  M.    (RUN  No.  19.) 


FIG.  2.— 205  R.  P.  M.    (RUN  No.  20-1.) 
COMPARISON    OF    JACK    PINE    PULPS    GROUND    AT    DIFFERENT   SPEEDS. 


Forest  Service,  U.  S.  Dept.  of  Agriculture— Mechanical  Pulp. 


PLATE  IX. 


FIG.  1.— JACK  PINE  GROUND  WOOD.    (RUN  No.  14-1.) 


FIG.  2.— JACK  PINE  GROUND  WOOD.    (RUN  No.  13-1.) 


Forest  Service    U.  S.  Dept.  of  Agriculture — Mechanical  Pulp. 


PLATE  X. 


mm 

i  -  I  *  \r  •  •  .'•  ,\> 


FIG.  1.— JACK  PINE  GROUND  WOOD.    (RUN  No.  7-1.) 


FIG.  2.— JACK  PINE  GROUND  WOOD.    (COMMERCIAL  RUN  No.  24.) 


Forest  Service,  U.  S.  Dept.  of  Agriculture— Mechanical  Pulp. 


PLATE  XI. 


FIQ.  1.— HEMLOCK  GROUND  WOOD.    (RUN  No.  41.) 


'-'--'-^^  ••-  ,  -^.,  -         "  ••••'>•-•»-*.  'l*-    -' 


FIG.  2.— HEMLOCK  GROUND  WOOD.    (COMMERCIAL  RUN  No.  14-1.) 


Forest  Service,  U.  S.  Dept.  of  Agriculture — Mechanical  Pulp. 


PLATE  XII. 


.:  J^fegj 
FIG.  1.— HEMLOCK  GROUND  WOOD.    (COMMERCIAL  RUN  No.  8.) 


FIG.  2.— HEMLOCK  GROUND  WOOD.    (RUN  No.  2.) 


Forest  Service,  U.  S.  Dept.  of  Agriculture— Mechanical  Pulp. 


PLATE  XIII. 


' 


FIG.  1.— HEMLOCK  GROUND  WOOD.    (COMMERCIAL  RUN  No.  30  ) 


FIQ.  2.— HEMLOCK  GROUND  WOOD.    (COMMERCIAL  RUN  No.  50.)    USED  IN  ACCOMPANYING 

PAPER  SAMPLE. 


Forest  Service,  U.  S.  Dept.  of  Agriculture — Mechanical  Pulp. 


PLATE  XIV. 


FIG.  1  .—GROUND-WOOD  PULP,  ONE-THIRD  SPRUCE,  TWO-THIRDS  HEMLOCK.    (RUN 

No.  46 A.) 


FIG.  2.— GROUND-WOOD  PULP,  ALL  HEMLOCK.    (RUN  No.  46e.) 


/.  "%, 


IMfei^ 


^^/^  •-  / 

(^^*£        ^i  ~y- 


FIG.  3.— GROUND-WOOD  PULP,  ALL  SPRUCE.    (RUN  No.  46c.) 


Forest  Service,  U.  S.  Dept.  of  Agriculture— Mechanical  Pulp. 


PLATE  XV. 


FIG.  1.— ONE-THIRD  SPRUCE,  TWO-THIRDS  HEMLOCK.    (COMMERCIAL  RUN  No.  46A.) 


*V3 


FIG.  2.— ONE-THIRD  HEMLOCK,  ONE-THIRD  JACK  PINE,  ONE-THIRD  SPRUCE.    (COMMERCIAL 

RUN  No.  51.) 


^Ti&^i?  •      ^A--.  ••'••?;*    •••-.    .vvt-   '^  i-^  .-m .-^JW,-- '•**•    -v 

t  ::J    '^    V^SI  SW:^^' 

s>^^        -<,;     v-  .*;-,' :v'..jf3^r/>  iV-^k     rv>. 


FIG.  3.— ONE-THIRD  JACK  PINE,  TWO-THIRDS  HEMLOCK.    (COMMERCIAL  RUN  No.  52.) 

MIXED    GROUND-WOOD    PULPS    USED    IN    ACCOMPANYING    PAPER 

SAMPLES. 


JACK    PINE   AND    HEMLOCK    FOR    MECHANICAL   PULP.  17 

Throughout  the  experiments,  particularly  the  commercial  tests,  it 
was  found  that  the  pulp  of  same  appearance  as  regards  fiber  and  of 
the  same  apparent  strength  can  be  obtained  by  using  burrs  of 
different  design  and  fineness  of  cut,  provided  the  grit  of  the  stv,  is 
in  each  case  the  same.  For  example,  during  the  commercial  tests 
the  stone  was  burred  at  different  times  with  different  types  of  burrs, 
and  the  grinding  in  each  case  was  found  to  require  the  consumption 
of  the  same  amount  of  power.  The  production  per  day  was  the  same 
also,  provided  the  grit  was  brought  to  the  same  condition  of  sharpness 
and  the  other  variables  were  kept  constant. 

During  some  of  the  preliminary  tests  the  surface  of  stone  was 
dulled  with  a  fire  brick,  as  is  often  done  in  mills.  This  appears  to 
have  been  unnecessary ;  in  fact,  the  result  is  detrimental  rather  than 
beneficial. 

Better  pulp  was  obtained  and  the  production  was  increased  slightly 
by  crushing  the  tops  of  the  ridges  formed  in  burring  by  means  of  a 
solid,  smooth  bush  roll.  This  method  does  not  smooth  off  the  indi- 
vidual particles  of  sand  on  the  stone  as  duUing  with  the  brick  does, 
but  rather  sharpens  them .  During  the  tests  conducted  on  mixed  woods 
a  surface  obtained  by  the  use  of  a  three- to- the- inch  straight-cut  solid 
burr  and  a  12-cut  spiral  burr  was  used.  The  stone  was  first  dressed 
with  a  three-to-the-inch  burr,  forming  grooves  in  the  stone  approxi- 
mately one  thirty-second  inch  deep;  then  the  portion  of  the  stone 
between  these  depressions  was  roughed  with  a  12-cut  spiral  burr. 
This  caused  the  grit  to  stand  out  and  gave  a  maximum  of  useful 
grinding  surface.  The  pulp  obtained  with  this  surface  was  almost 
entirely  free  from  shives,  and  the  fibers  were  long  and  fine.  The  sur- 
face of  stone  used  during  these  tests  is  shown  in  Plate  III,  figure  2. 

A  great  deal  of  experimentation  still  remains  to  be  done,  not  only 
with  burrs  of  different  cut  and  design,  but  more  especially  with  stones 
of  different  grits,  since  it  appears  that  the  grit  is  more  responsible 
for  the  quality  of  pulp  obtained  than  any  other  variable  feature  in  its 
production. 

Where  the  pulp  stone  is  deep  burred,  however,  the  grit  is  not  so 
important  a  factor  of  quality.  When  the  power  consumed  in  making 
a  ton  of  bone-dry  pulp  is  as  low  as  50  to  60  horsepower,  the  added 
production  which  must  be  secured  to  bring  the  power  to  this  low 
value  is  obtained  through  the  action  of  the  ridges  on  the  stone  and 
not  through  the  grit.  When  it  is  desired  to  manufacture  a  pulp  of 
high  quality,  however,  it  is  the  grit  of  the  stone  and  the  manner  of 
raising  it  which  must  be  considered.  The  type  of  burr  used  and  the 
depth  of  dressing  both  influence  production,  but  it  is  only  the  latter 
that  influences  the  quality.  When  the  pulp  stone  has  been  dressed 
so  as  to  provide  just  sufficient  depression  to  carry  away  the  ground 
23688°— 12 2 


18  JACK    PINE    AND   HEMLOCK    FOR    MECHANICAL   PULP. 

wood  a  high-grade  pulp  will  be  produced,  providing  the  grit  of  the 

stone  is  suitable,  irrespective  of  the  style  of  the  burr  and  within 

~vable  limits  of  the  pressure  used.     It  is  not  impossible  to  con- 

jf  an  artificial  stone  which  could  be  used  continually  without 

n,   —Jig,   which   would   clear  itself   without   having   depressions   or 

ridges,  and  which  would  have  the  correct  size  and  kind  of  grit  to  give 

the  maximum  production  and  best  quality. 

TEMPERATURE. 

The  temperature  of  grinding,  it  is  said,  has  much  to  do  with  the 
quality  and  quantity  of  pulp  obtained,  and  many  manufacturers 
insist  that  it  is  impossible  to  secure  a  tough,  strong  fiber  with  anything 
but  the  hot  grinding  process.  It  was  noted  in  the  experiments  that 
the  rate  of  production  was  not  nearly  as  great  at  a  low  temperature 
as  it  was  after  a  high  one  was  reached.  However,  it  was  impossible 
to  detect  microscopically  any  difference  in  the  fibers  themselves.  As 
has  been  said,  the  only  observations  made  on  cold  grinding  were 
while  the  stone  was  warming  up,  and  on  this  account  it  is  impossible 
to  say  definitely  what  particular  advantages  or  disadvantages,  if  any, 
lie  in  the  hot  grinding  process. 

UNDETERMINED    FACTORS. 

Since  the  experimental  work  on  hemlock,  jack  pine,  and  spruce 
was  started  a  number  of  factors  which  more  or  less  influence  the 
quality  and  the  rate  of  production  of  pulp  have  made  themselves 
evident.  These  are  the  rate  of  growth  of  the  wood,  moisture  content 
of  the  wood,  size  of  wood  ground,  temperature  of  grinding,  the  thick- 
ness of  stock  in  the  grinder  pit,  and  the  grit  of  the  pulp  stone,  the 
last  undoubtedly  being  the  most  important.  All  of  these  variables 
will  be  studied  in  future  experiments,  though  the  grit  of  the  pulp 
stone  is  the  one  which  will  probably  receive  the  greatest  attention. 
It  is  doubtful  whether  this  very  important  item  in  the  production  of 
ground  wood  has  been  given  sufficient  consideration  by  manufacturers. 

MICROSCOPIC     COMPARISON     OF     EXPERIMENTAL     PULPS     AND 
COMMERCIAL    STANDARDS. 

STANDARD    PULPS. 

Since  it  was  necessary  to  have  some  means  of  comparing  the 
experimental  pulps  produced  with  commercial  products,  portions  of 
the  samples  obtained  from  manufacturers  were  photographed,  in  an 
endeavor  to  classify  the  fibers  according  to  their  quality.  It  was 
found  that  there  is  a  more  or  less  regular  grading  of  the  material 
from  long,  fine  fiber  to  pulp  which  is  almost  a  powder.  It  is  probable 


JACK    PINE   AND    HEMLOCK    FOR    MECHANICAL   PULP. 


19 


thai/  each  of  the  various  grades  of  pulp  has  its  particular  use  in  cer- 
tain qualities  of  paper,  though  no  attempt  has  been  made  to  classify 
them  according  to  uses.  The  standards  selected  are  shown  .  ites 
IV,  V,  and  VI;  in  each  case  the  fibers  are  enlarged  15  time  For 
the  purpose  of  comparison  the  spruce  sulphite  standard  fiber  is  shown 
in  Plate  IV,  figure  1,  and  the  No.  1  spruce  ground- wood  standard  in 
figure  2.  It  is  indeed  very  seldom  that  a  sample  of  pulp  is  obtained 
which  corresponds  to  the  No.  1  spruce  ground- wood  standard.  As 
will  be  noted,  the  fibers  are  very  similar  to  the  sulphite  fibers,  although 
there  is  a  certain  amount  of  short  material  and  coarse  fiber  present 
which  does  not  occur  in  the  sulphite  pulp. 

Plate  V  shows  the  No.  2  ground- wood  standard  and  No.  3  coarse 
ground- wood  standard.  The  No.  2  differs  from  the  No.  1  standard 
only  in  the  amount  of  short  fiber  and  coarse  fiber  present,  the  No.  2 
having  larger  amounts  of  these  two  kinds.  The  coarse  standard 
needs  no  description.  It  is  a  kind  of  fiber  often  made  by  mills  during 
their  low-water  periods  in  order  to  maintain  production  with  less 
power  consumption. 

The  No.  4,  medium  ground-wood  standard,  and  the  No.  5,  fine 
ground-wood  standard,  seem  to  follow  in  logical  sequence  those  pre- 
viously given.  The  No.  4  standard  has  the  appearance  of  being  a 
mixture  of  No.  3  and  No.  5.  The  No.  5,  as  will  be  noted,  contains  an 
extremely  small  amount  of  fiber  and  is  composed  largely  of  dust  and 
short-fiber  particles. 

Table  2  gives  the  data  furnished  by  the  manufacturers  of  the 
various  pulp  samples  selected  as  standards.  These  data,  for  the 
most  part,  are  only  approximate,  but  they  will  serve  to  give  some 
idea  of  the  conditions  under  which  the  material  was  produced. 

TABLE  2. — Conditions  of  manufacture  of  spruce  ground-wood  standards. 


Number  of  stand- 
ard. 

Make  of  grinder. 

1 

Size  of  cylinders. 

& 

*£» 
o 

§£ 

i"3 

35 
40 
45 
60 
90 

Equivalent  pres- 
sure on  14-inch 
cylinder. 

Kind  of  stone. 

Kind  of  burr. 

Size  of 
stone. 

Number  o 
ets. 

§3 
~<v 

5 

54 
54 
54 
54 
54 

Pm 

1 
2 
3 
4 
5 

Friction   Pulley   &   Machine 
Works. 
Carthage  Machine  Co  

3 
3 
3 
3 
3 

16 
16 
18 
14 
10 

45.7 
52.2 
74.4 
60.0 
45.9 

Lombard 

Washers  

27 
26 
27 
251 
181 

Lombard     and 
Manufacturers' 
Lombard  

Empire 

Solid  spiral  cut  8 
to  1  inch. 
Diamond  point 
cut  6  to  1  inch. 
Straight  cut  7  to  1- 
inch. 
Diamond  point  7 
to  1-inch  and  5 
to  1-inch. 

Dayton  Globe  Iron  Works  
Carthage  Machine  Co 

Friction    Pulley  &  Machine 
Works. 

Greeley,      New 
Castle. 

20  JACK   PINE   AND   HEMLOCK   FOR   MECHANICAL  PULP. 

TAB^E  2. — Conditions  of  manufacture  of  spruce  ground-wood  standards — Continued. 


R 

i 

I 

"3 

1 

"S-c 

1* 

Make  of  grinder. 

rotations 
nute  of  s 

ii 
•§,« 

I1 

sf 

&4&0 

"o 

Grade  of  paper. 

r-t 

&  5 

s 

o 

M 

s 

* 

P3 

£ 

H; 

g 

s 

1 

Friction  Pulley  &  Machine  Works  

180 

2,545 

90 

160 

.012 

Do  not  make  paper. 

f  190 

2,686 

1 

2 

Carthage  Machine  Co  

\    to 

to 

\        75 

175 

.012 

Poster 

1  200 

2,827 

! 

3 

Dayton  Globe  Iron  Works  

145 

2,050 

i  300 

.010 

News 

4 

Carthage  Machine  Co 

270 

3  817 

100 

075 

Do 

5 

Friction  Pulley  &  Machine  Works  

220 

3,110 

70 

Cold. 

.011 

Specialties.     Some 

coated,  requiring 

a  soft   and   fine 

pulp. 

1  To  grinder. 


JACK   PINE    PULP. 


Plates  VIII,  IX,  and  X  show  six  samples  of  ground-wood  fiber 
obtained  from  jack  pine.  The  data  taken  during  these  tests  are  given 
in  Table  4.  There  is  a  very  striking  likeness  between  the  fiber 
obtained  from  jack  pine  and  that  from  spruce.  Especially  is  this 
true  of  the  fiber  secured  by  using  the  natural  grit  of  the  pulp  stone 
without  any  burring.  Tests  Nos.  7-1,  19,  and  13-1  were  run  by 
using  an  excessive  amount  of  power  and  by  sacrificing  the  rate  of 
production.  This  wood  was  ground,  however,  in  the  dry  state,  and 
unquestionably  the  same  quality  of  fiber  could  be  obtained  with 
increased  production  and  lower  horsepower  consumption  per  ton  if 
it  was  soaked  or  steamed.  The  fibers  obtained  in  tests  Nos.  20-1, 
commercial  run  No.  14-1,  and  commercial  run  No.  24  compare  favor- 
ably with  the  No.  4  standard,  and  the  production  and  power  con- 
sumption are  more  nearly  those  obtained  commercially.  There  is 
more  short  material  than  is  found  in  the  No.  1  or  No.  2  standards,  but 
still  the  fiber  is  long  and  fine,  and  appears  to  have  considerable 
strength.  The  illustrations  show  some  of  the  better  fibers  obtained. 
Of  course  pulp  has  been  made  in  the  laboratory  which  was  fully  as 
fine  as  that  shown  as  the  No.  5  standard.  Some  has  been  made  also 
which  is  fully  as  coarse  as  the  No.  3.  However,  this  is  rather  the 
exception  than  the  rule. 

The  jack  pine  fiber  shown  in  Plate  X  (run  No.  7-1)  was  the  most 
pleasing  in  appearance  when  in  the  pulp  lap,  and  was  generally  con- 
sidered to  possess  the  best  quality.  The  rate  of  production,  however, 
was  so  very  low,  and  the  horsepower  consumption  so  high,  that  it  has 
no  commercial  importance. 


JACK    PINE,  AND   HEMLOCK   FOR    MECHANICAL   PULP.  21 

HEMLOCK   PULP. 

Plates  XI,  XII,  and  XIII  show  hemlock  fibers  which  were  ov  '  i  °,d 
during  the  tests.  Undoubtedly  the  most  notable  feature  is  *  ge 

amount  of  fine  material  present  as  compared  with  the  jack  pin-  .cim- 
ples.  Hemlock  grinds  short  and  fine  to  a  far  greater  extent  than 
either  spruce  or  jack  pine.  While  there  are  a  great  many  long  fibers 
present,  they  are  not  sufficient  in  number  to  give  a  strong  and  tough 
pulp.  A  certain  amount  of  short  material  is  necessary,  however,  for 
news  paper,  and  it  is  this  material  which  gives  a  good  finish.  The 
finish  on  the  paper  made  from  the  hemlock  pulp,  commercial  run  No. 
8,  was  exceedingly  good;  in  fact,  the  superintendent  of  the  mill  where 
the  sample  was  run  pronounced  it  better  than  the  standard  news.  It 
will  be  seen  that  there  is  a  regular  gradation  in  the  length  of  fibers 
from  the  long  to  the  almost  powder  form.  On  certain  of  the  illustra- 
tions of  hemlock  fiber  black  spots  composed  of  a  great  deal  of  fine 
fiber  will  be  noticed.  These  are  the  result  of  drying  the  pulp  before 
making  slides,  it  being  impossible  entirely  to  beat  out  the  fiber  after 
drying.  When  the  material  was  in  the  form  of  pulp  laps  there  was 
no  marked  difference  in  the  pulps.  However,  as  with  the  jack-pine 
samples,  only  the  better  grades  of  pulp  obtained  are  shown.  The 
sample  of  pulp  illustrated  in  Plate  XIII,  figure  2  (commercial  run  No. 
50),  is  fairly  representative  of  the  pulp  which  it  is  possible  to  make 
from  hemlock  under  the  conditions  described. 

MIXED    PULPS. 

Plate  XIV  shows  three  photomicrographs  of  fibers  obtained  under 
exactly  the  same  conditions  of  pressure,  speed,  and  surface  of  stone. 
The  temperature  and  other  minor  variables  were  also  kept  as  nearly 
alike  as  possible. 

Figure  1  shows  fibers  obtained  by  grinding  hemlock  in  two  of  the 
grinder  pockets  and  spruce  in  the  third  (run  46a) .  Upon  determina- 
tion it  was  found  that  the  pulp  contained  34  per  cent  spruce  and  66 
per  cent  hemlock.  Figure  2  shows  hemlock  fiber  obtained  under  the 
same  conditions  (run  46&)  as  the  first  test,  and  figure  3  shows  a  number 
of  spruce  fibers  (run  No.  46c).  The  hemlock  fiber  is  considerably 
shorter  than  the  spruce  and  there  are  more  shives  present.  In  the 
composite  sample  the  hemlock  is  decidedly  in  evidence. 

Plate  XV  shows  three  fibers  obtained  by  grinding  different  woods 
in  different  pockets  of  the  pulp  grinder.  Commercial  run  No.  46a  is 
composed  of  a  mixture  one-third  spruce  and  two-thirds  hemlock; 
commercial  run  No.  51  is  composed  of  one- third  jack  pine,  one-third 
spruce,  and  one-third  hemlock;  commercial  run  No.  52  of  one-third 
jack  pine  and  two-thirds  hemlock.  All  of  these  pulps  when  in  the 


22  JACK   PINE   AND   HEMLOCK   FOR   MECHANICAL   PULP. 

lap  appeared  to  be  a  very  good  quality;  in  fact,  it  will  be  seen  that  the 
fiber  of  which  they  are  composed  is  of  good  length  and  that  there  is 
no  as  much  short  material  present  as  there  is  in  the  samples 

of  pulp. 

Coi  aorcially  it  would  be  possible  to  obtain  better  mixed  pulps  by 
grinding  the  different  woods  in  separate  grinders  and  preparing  the 
stones  so  as  to  obtain  the  best  quality  of  pulp  from  each  wood. 

It  has  been  found,  by  comparing  the  samples  submitted  by  Amer- 
ican manufacturers  with  the  standards  chosen,  that  5  per  cent  can 
be  classed  as  No.  1  pulp,  12  per  cent  as  No.  2  pulp,  12  per  cent  as  No. 
3  pulp,  61  per  cent  as  No.  4,  and  10  per  cent  as  No.  5.  Comparison 
of  the  experimental  pulps  with  the  commercial  standards  shows  that 
mixed  pulps  particularly  compare  well  with  the  No.  4  standard,  for 
which  there  is  evidently  the  greatest  demand. 

SAMPLES  OF  PAPER,  PRODUCED. 

In  order  to  determine  the  adaptability  of  the  pulps  obtained  in  the 
experiments  to  the  manufacture  of  paper,  a  number  of  test  paper  runs 
were  made  with  the  pulps  which  gave  greatest  promise.  Samples  of 
the  paper  obtained  accompany  this  report.  All  of  the  sheets  of  news 
paper  were  made  on  a  machine  in  the  Port  Edwards  mill  of  the 
Nekoosa-Edwards  Paper  Co.  This  machine  is  116  inches  wide,  and 
the  sheet  produced,  trimmed,  was  109  inches.  The  machine  was 
operated  at  a  speed  of  465  feet  per  minute,  and  no  changes  were  made 
in  weight  of  sheet  or  speed  after  the  beginning  of  the  test;  in  fact, 
throughout  the  runs  the  conditions  were  maintained  as  nearly  con- 
stant as  possible.  The  finish  on  the  paper  was  obtained  by  passing 
the  sheet  nine  times  through  a  12-roll  calender  stack.  In  each  case 
three  1,500-pound  beaters  of  stock  were  run  into  sheet  in  order  to 
have  the  test  continuous  over  sufficient  time  to  give  an  idea  of  its 
operation  on  the  paper  machine.  It  was  intended  to  by-pass  the 
Jordan  engine,  but  this  being  impossible,  the  stock  was  passed 
through  the  engine  and  the  roll  set  up  only  slightly. 

Running  changes  were  made  in  each  test,  and  no  difference  was 
found  with  any  of  the  sheets  excepting  jack  pine.  This  material 
was  somewhat  pitchy,  and  after  an  hour's  run  it  was  necessary  to 
remove  the  dandy,  since  it  began  to  pick  up  stock.  All  of  the  papers 
were  free  on  the  wire  and  caused  no  trouble  whatever. 

The  samples  of  paper  containing  spruce  were  made  up  for  the  pur- 
pose of  comparison.  It  will  be  seen  that,  with  the  exception  of  color, 
the  sheets  differ  little,  and  it  is  reasonable  to  suppose  that  the  color 
could  be  improved.  Allowance  should  be  made  for  the  appearance 
of  the  sheets  as  regards  brown  shives,  these  being  due  to  the  hem- 
lock sulphite  used,  and  not  to  the  ground  wood.  Data  on  the  beater 
''furnish"  for  the  various  papers  are  given  in  Table  10.  Table  3 
gives  a  comparison  of  strength  of  the  various  sheets. 


JACK    PINE   AND   HEMLOCK    FOR    MECHANICAL   PULP. 


The  samples  of  butcher's  manila  and  No.  2  white  manila  given  were 
made  by  the  Nekoosa-Ed wards  Paper  Co.,  the  furnish  being  sho^     :TI 
Table  10.     These  samples  are  meant  merely  to  give  an  idea  of 
can  be  obtained  when  mixtures  of  hemlock  and  spruce  are  usea. 

The  strength  of  all  of  the  sheets,  with  the  exception  of  the  one  made 
up  of  hemlock  sulphite  and  jack-pine  ground  wood,  compares  well  with 
standard  news  paper.  The  paper  from  run  No.  24  has  another  decid- 
edly objectionable  feature,  and  that  is  the  loss  of  finish  occasioned  by 
rubbing  the  sheet  with  the  hand.  The  fibers  under  this  treatment 
fuzz  up,  and  considerable  powder  and  short  fiber  fall  off.  Several  of 
the  other  sheets  have  this  same  peculiarity,  but  if  more  size  were 
added  this  trouble  would  probably  be  eliminated. 

The  experimental  papers  have  not  yet  been  tested  on  high-speed 
presses,  and  this  must  be  done  before  accurate  knowledge  of  the  value 
of  the  several  sheets  can  be  had. 

However,  after  having  obtained  news  paper  of  the  quality  of  the 
attached  samples  from  hemlock,  jack  pine,  and  mixtures  of  these 
woods  without  changing  in  any  way  present  commercial  practice,  it 
seems  beyond  doubt  that  these  woods  may  be  advantageously  used 
either  singly  or  in  various  combinations,  at  least  in  the  cheaper  grades 
of  paper. 

TABLE  3. — Strength,  weight,  and  thickness  tests  on  experimental  papers. 


i 

Mullen  test. 

Schopper  test. 

,d 

'  d 

i 

1 

1 

|| 

S 

Lengthwise. 

Crosswise. 

•^ 

Q 

^ 

o  o 

,rj 

fS 

T3 

^ 

g.s 

OT 

a 

Is 

d  >> 

i 

d  s>> 

i 

1 

mlock  sulpr 

•uce  ground 

^S 
1 
I 

§ 

0. 

ight  per  rea 
24  by  36 

erage  thicki 

p 

fl 

o 

1 

"& 

erage  stretc] 

erage  load  o 
trip  18  b 
.65  cm. 

!! 

<3  d° 

erage  stretc 

erage  load  o 
trips  18  b 
.65  cm. 

p 

03  fcjQ 

g 

o> 

<D 

0 

^> 

r3 

B 

> 

>  Wl-< 

>-~ 

!> 

>  WH 

£*  'r-l 

O 

w 

00 

w 

^ 

£ 

«5 

M 

CQ 

<J 

<5 

<t 

< 

A 

<1 

P.ct. 

P.  c/i. 

P.  c«. 

P.ct. 

Lbs. 

Inches. 

i6s. 

P.ct. 

Kilos. 

Meters. 

P.ct. 

Kilos. 

Met's. 

1(T 

5 

95 

32 

0.  0033 

11 

0.344 

0.8 

2.95 

3,687 

1.4 

1.765 

2,254 

1 

25 

75 

33 

.0035 

13.2 

.400 

.95 

3.49 

4,043 

1.22 

.780 

2,150 

94 

25 

75 

33 

.0038 

8.2 

.249 

.95 

2.53 

3,251 

1.08 

.305 

690 

46 

25 

25 

50 

33 

.0037 

11.4 

.345 

1.05 

3.495 

3,907 

1.42 

.755 

,987 

50 

25 

75 

34 

.0035 

10.2 

.300 

1.11 

3  615 

4  111 

1  17 

555 

819 

51 

25 

25 

25 

25 

32 

.0035 

9.7 

.303 

.95 

2.855 

3,495 

1.24 

.410 

,692 

52 

25 

50 

25 

33 

.004 

9.9 

.300 

.98 

3.005 

3,606 

1.43 

.330 

,640 

All  of  the  above  are  averages  of  10  determinations. 

SUMMARY   OF   DATA. 

Tables  4,  5,  6,  7,  8,  and  9  show  compilations  of  the  data  secured 
during  tests  on  hemlock,  jack  pine,  and  mixtures  of  these  two  woods 
with  spruce.  The  results  of  tests  under  many  different  conditions  of 
speed,  pressure,  and  surface  of  stone  are  given.  In  a  number  of  cases 
the  data  on  production  and  power  consumption  do  not  agree  with  that 
taken  at  another  time  and  under  the  same  conditions  of  pressure, 


JACK   PINE   AND    HEMLOCK   FOE    MECHANICAL   PULP. 


speed,  and  type  of  burr.  In  all  of  these  instances  the  differing  values 
onii  N>  accounted  for  by  the  fact  that  although  the  same  kind  of  burr 

)d,  the  stones  were  of  different  sharpness. 

s  been  found  difficult  to  duplicate  in  one  test  the  surface  of 
si^  ,  used  in  another  under  the  same  conditions  and  obtain  the  same 
production  with  the  same  power  consumption.  In  fact,  the  pro- 
duction factors  vary  greatly  over  short  periods  as  a  result  of  the  vary- 
ing attention  given  by  the  grinder  man.  On  this  account  the  power 
and  production  data  in  the  tables  can  be  applied  to  commercial  plants 
only  approximately.  If  a  grinder  is  operating  under  the  conditions 
of  any  of  the  commercial  tests  shown  in  Tables  5,  6,  and  7,  however, 
the  data  given  will  closely  approximate  the  actual  working  conditions. 

TABLE  4. — Qualitative   and  quantitative  tests  on  jack  pine — Power  consumption  and 

production. 


Kind  of 
stone. 

Run  number. 

Kind  of  burr. 

Pressure  on  14-inch 
cylinder. 

Pressure  per  square 
inch,  pocket  area. 

Revolutions  per 
minute. 

Peripheral  speed 
per  minute. 

Average  horsepower 
to  grinder. 

Bone-dry  pulp  in  24 
hours. 

Horse  power  per  ton 
bone-dry  pulp  in 
24  hours. 

Bone-dry  pulp  per 
100  cubic  feet  borie- 
dry  wood. 

Weight  per  cubic 
foot  bone-dry 
wood. 

Average  tem  pera- 
ture'bf  grinding. 

Size  of  screen  slots. 

Manufac- 
turers'. 
Do 

1 
2 

Natural    sur- 
face, 
do 

Lbs. 

20.0 

30.0 

Lbs. 
8.20 

12.30 

151.  0 
151.0 

Feet. 
2,100 

2,100 

Tons. 

Lbs 

Lbs. 

•JK 
140.0 

147.0 

Inch. 

(i) 

Do 

3 

do 

39  0 

10.00 

150  0 

2,090 

176.  0 

(i) 

Do 

3-1 

do  .. 

39.3 

16.  10 

151.0 

2,100 

176.0 

(i) 

Do 

4 

do 

50  0 

20.50 

150.6 

2,100 

196.  0 

(i) 

Do 

5 

do  ... 

60.0 

24.65 

151.0 

2,  100 

199.  0 

(i) 

Do 

6 

do 

60  0 

24.  65 

171.0 

2,380 

196.0 

(i) 

Do 

6-1 

do  

60.0 

24.65 

171.0 

2,370 

201.0 

(i) 

Do 

7 

do 

50  0 

20.50 

171.0 

2,370 

199.0 

C1) 

Do 

7-1 

do  

50.0 

20.50 

172.0 

2.380 

256.0 

1.305 

196.2 

1,820 

25.27 

197.0 

0.  012 

Do 

7-2 

do 

50.0 

20.50 

172  0 

2,380 

245  0 

1.263 

193.  6 

2,  150 

25.  57 

183.0 

.012 

Do 

8 

do 

60  0 

24  65 

203  0 

2,810 

198.0 

(i) 

Do 

8-1 

do 

60.0 

24.  65 

203.  0 

2,810 

191.0 

(i) 

Do 

9 

do 

50  0 

20.  50 

202  0 

2,800 

205.0 

(i) 

Do 

10 

do.... 

75.0 

30.80 

202.0 

2,800 

185.0 

(i) 

Do  
Do 

11 
11-1 

Diamond 
point,   6  to 
the  inch, 
do  

60.0 
60.0 

24.  65 
24.  65 

152.  5 
154.0 

2,100 
2,100 

380.5 
360.  5 

6.075 

59.3 

148.0 
146.0 

.012 
.012 

Do 

do 

50  0 

20  50 

152  5 

2  100 

350  0 

5  225 

67  0 

145.0 

.012 

Do 

12-1 

do!!!  '!!.... 

50.0 

20.50 

154.0 

2,100 

359.0 

7.030 

51.0 

179.0 

.012 

Do 

13 

do.  . 

40.0 

16.40 

152.5 

2,100 

260.  0 

3.028 

85.9 

138.  2 

.012 

Do.      .. 
Do 

13-1 
14 

do  
do  

40.0 
50.0 

16.  40 
20.50 

153.  5 
173.0 

2,100 
2,380 

299.0 
324.0 

2.  670 
4.7K 

112.0 

68.8 

195.0 
154.0 

.012 
.012 

Do 

14-1 

do 

50.0 

20.  .50 

174.0 

2,380 

398.0 

5.  046 

78.8 

166.0 

.012 

Do 

15 

do  

60.0 

24.65 

173.  0 

2,380 

395.  5 

6.290 

61.8 

138.  0 

.012 

Do 

15-1 

do.  . 

60.0 

24.  65 

174.0 

2,380 

461.0 

5.500 

83.8 

158.0 

.012 

Do.      .. 
Do.      .. 
Do 

16 
16-1 
17 

do  
do  

do 

40.0 
40.  ( 
40.0 

16.40 
16.  40 
16.  40 

203.  5 
205.  0 
173.0 

2,800 
2.800 
2.380 

362.  5 
375.0 
289.  0 

5.450 
5.  360 
3.834 

66.4 
70.0 
75.5 

147.0 
200.0 
143.  0 

.012 

.012 
.012 

Do  

17-1 

.      do  

40.0 

16.40 

174.0 

2,380 

332.0 

4.  350 

76.3 

178.0 

.012 

Do 

18 

do    . 

50.0 

20.  -50 

204.0 

2,800 

407.5 

6.910 

59.0 

143.0 

.012 

Do  

18-1 

...do.... 

50.0 

20.50 

205.0 

2,800 

414.0 

6.360 

65.0 

193tO 

.012 

Do 

19 

do 

30  0 

12  30 

15°  5 

2  100 

201  0 

2.045 

98  3 

149.0 

.012 

Do 

20 

do 

30.0 

12.30 

205.0 

2,800 

313.0 

5  320 

58.8 

178.0 

.012 

Do  
Do. 

20-1 
21 

do  

do.... 

30.0 
30.0 

12.30 
12.30 

205.  0 
174.0 

2,800 
2,380 

304.0 
269.  5 

3.620 
4.810 

83.8 
56.0 

2,370 

24.90 

198.0 
172.0 

.012 
.012 

Do 

22 

do 

60.0 

21.  64 

205.  0 

2,800 

481.0 

7.320 

65.8 

1S5.  0 

.012 

Do  

Lombard 

23 

24 

do  

40.0 
{  40.1 

16.  40 
16.40 

205.0 
J175.  0 

2,800 
2,445 

249.0 
395.  0 

4.110 
4.305 

84.9 
91.8 

2,220 

25.60 

206.  0 
176.3 

.012 
.012 

\  45.  0 

18.  46 

/ 

1  Unscreened. 


JACK    PINE   AND   HEMLOCK   FOR   MECHANICAL  PULP. 


25 


TABLE  5. — Qualitative  and   quantitative    tests  on  hemlock — Power  consumption  and 

production. 


Kind  of 
stone. 

m  number. 

Kind  of  burr. 

essure  on  14-inch 
cylinder. 

essure  per  square 
ich,  pocket  area. 

evolutions  per 
minute. 

ripheral  speed 
per  minute. 

^erage  horsepower 
to  grinder. 

>ne-dry  pulp  in  24 
hours. 

C  fl 

!* 
a= 

££E 

111 

o££ 

M 

P£ 
§|d 

t£  ° 

m 

1! 
*! 

HI 

to 
&o 

££ 

0>    p 

v 
jo 

C 

1 
g 

o 

o> 

tf 

Pi 

(2 

£ 

< 

PQ 

W 

« 

<J 

CQ 

0 

Straight    cut, 

Lbs. 
50 

Lbs. 

20.50 

170.0 

Feet. 
2,380 

288.0 

Tons. 

Lbs. 

Lbs. 

°F. 
131.  0 

Inch. 

(i) 

turers'. 
Do 

1 

10     to     the 
inch, 
do  

30 

12.30 

100.0 

1,400 

1.54.0 

126.0 

C1) 

"Do 

2 

do 

30 

12  30 

150  0 

2  100 

202  0 

143.0 

(2) 

Do 

3 

do 

30 

12.30 

200.0 

2,800 

275.  0 

150.0 

2) 

Do 

4 

do 

30 

12  30 

2°5  0 

3  150 

301  0 

155.0 

M 

Do  

5 

do  

20 

8.20 

150.0 

2,100 

169.  5 

1.011 

167.7 

159.0 

2) 

Do 

6 

do 

20 

8  20 

175  0 

2  450 

210  0 

1  380 

152  0 

170  C 

2) 

Do  

7 

do  

20 

8.20 

225.0 

3,150 

223.0 

1.295 

172.  0 

169.0 

2) 

Do 

2-1 

do  

30 

12.30 

150.0 

2,100 

254.0 

1.965 

129.0 

167.  C 

2) 

Do 

g 

do 

40 

16.40 

175.0 

2,450 

328.0 

3.055 

107.3 

166.0 

2) 

Do 

9 

do 

60 

21  65 

175  0 

2  450 

430  0 

4  730 

91  0 

168  0 

2) 

Do 

10 

Spiral  cut,  10 

20 

8.20 

100.0 

1  393 

87.3 

129,0 

(1) 

Do 

•  11 

to  the  inch, 
do 

40 

16.40 

175.  0 

2.440 

259.0 

1.430 

181.0 

170.0 

(2) 

Do 

12 

do  

50 

20.  50 

225.  0 

3,150 

368.  0 

2.475 

149.  0 

178.  0 

(*) 

Do 

13 

do    . 

60 

24.65 

225.  0 

3.150 

475  0 

3.  595 

132.0 

171.0 

(2) 

Do 

14 

do 

50 

20  50 

175  0 

2  440 

358  0 

3  395 

105  6 

166.  0 

H 

Do 

15 

do  .. 

60 

24.65 

175.0 

2,440 

397.0 

4.044 

98.4 

131.5 

(2) 

Do 

16 

do 

30 

12  30 

175  0 

2  44( 

243  0 

148.  5 

(2) 

Do 

do    . 

30 

12.30 

200.  0 

2,790 

297.0 

146.0 

M 

Do 

18 

do 

30 

12  30 

100  0 

1  390 

162  8 

158.0 

(2) 

Do 

19 

do    .. 

50 

20.50 

100  0 

1,390 

261.  0 

2.  470 

105.  7 

157.  0 

(2) 

Do 

20 

do 

40 

16  40 

200  0 

2  790 

377  0 

3  780 

99  7 

!«•>  0 

(2) 

Do 

21 

do  .. 

(50 

24.65 

100.6 

1,100 

281.0 

2.  810 

100.0 

160.0 

2 

Do 

22 

do 

50 

20  50 

150  0 

?  090 

366  0 

3  815 

96  0 

161  5 

w 

Do 

23 

D  i  a  m  o  n  d- 

40 

16.40 

175.0 

2,440 

347.0 

3.  360 

103.2 

159.0 

M 

Do 

24 

pointcut,  10 
to  the  inch, 
do 

50 

20  50 

175  0 

2,440 

394.0 

5.065 

77  7 

157.  0 

(2) 

Do.... 
Do 

25 
26 

do  

do 

60 
30 

24.  65 
12  30 

100.0 
200  0 

1,390 

2,782 

291.5 
315.0 

3.312 
2  945 

88.0 
107  0 

156.0 
163.0 

§ 

Do 

27 

do  

50 

2J.  50 

200.0 

2,782 

432.0 

5.400 

80.0 

160.5 

M 

Do 

28 

do 

60 

24.  65 

101  0 

1,408 

290.0 

168.0 

(2) 

Do  

Do  

29 
30 

do  

Straight  cut: 
4  to  the  inch. 

50 

1      40 

20.50 
16.  40 

175.  0 
175.0 

2,435 
2,435 

372.0 
319.0 

3.900 

81.8 

187.0 
145.  0 

0) 
(2) 

Do 

31 

10  to  the  inch 
do 

f 

60 

24  65 

100  0 

1  390 

269  0 

3  330 

80  9 

145  0 

(2) 

Do  
Do 

3? 
33 

do  

do 

6( 
50 

24.  65 
20  50 

100  0 
175  0 

1,390 
2,  435 

298.0 
376  0 

3.  120 
4  000 

95.5 
94  0 

155.0 
163.0 

(2) 
(2)' 

Do  

Do 

34 
35 

Spiral  cut,  8  to 
the  inch, 
do 

60 
60 

24.65 
24  65 

100.0 
100  0 

1,390 
1  390 

297.0 
284  0 

4.35C 
2  915 

68.3 
97  5 

135.0 
147  0 

(2) 
(2) 

Do..  .. 

36 

do    . 

60 

24.65 

150.0 

2,090 

417.0 

5.  130 

81.4 

152.  0 

(2) 

Do 

37 

do 

60 

24  65 

200  0 

2  782 

5°0  0 

6  890 

75  5 

154  0 

(2) 

Do  

38 

do 

50 

20.50 

84.3 

1,173 

212.0 

2.660 

79.7 

154.0 

M 

Do 

39 

do 

60 

24  65 

85  0 

1  183 

271  0 

2  955 

91  8 

150  0 

M 

Do  

40 

do  

50 

20.50 

100.0 

1,390 

285.  0 

3  0?5 

94  3 

156.0 

(2) 

Do 

41 

do 

50 

20  50 

150  0 

2  090 

379  0 

4  450 

85  2 

155  0 

(«) 

Do  

42 

do.. 

50 

20.50 

175.  0 

2,435 

429.0 

5.295 

81.1 

155.0 

(2) 

Do 

43 

do 

50 

90  50 

200  0 

2  782 

439  0 

5  4^5 

80  9 

145  0 

(2) 

Do  

Lombard  .  . 

Do.... 

44 
45 

47 

do  

Straight    cat, 
3  to  the  inch, 
do 

40 
40 

55 

16.  -10 
16.40 

22.60 

175.0 
200.0 

200  0 

2,  435 
2..800 

2,800 

359.0 
340.0 

516.0 

4.225 
2.  91f 

5.370 

85.0 
116.5 

96.2 

158.0 
159.0 

161.0 

H 

(2) 

Do  

48 

.  .  .do  

50 

20.50 

225.0 

3,145 

510.  0 

6.235 

81.8 

164.0 

© 

Do...... 

50 

Straight  cut,  3 
to  the  inch; 
spiral  cut,  12 
to  the  inch. 

50 

20.  50 

175.0 

2,445 

422.5 

5.300 

79.7 

2.070 

24.84 

170.6 

(2) 

1  Unscreened. 

2  Size  of  screen  slots,  0.065  and  0.012. 


26 


JACK   PINE   AND   HEMLOCK   FOR    MECHANICAL   PULP. 


TABLE  6. — Commercial  tests  on  jack  pine — Power  consumption  and  production. 

GREEN  MATERIAL. 


| 

S, 

i 

1 

i 

<N 

a  fl 
3-1 

^ 

J£ 

^ 

Si 

2 

Kind  ol 
stone. 

mercia 
numL 

Kind  of  burr. 

4  . 

^% 

CTS 

o  a 

If 

s  2 
S1* 

tH    <U 

1* 

ff>f$ 

olutions 
minute. 

pheral  sp 
per  minute. 

rage  horsepo^ 
to  grinder. 

e-dry  pulp  ir 
hours. 

sepower  per 
ne-dry  pulp 
hours. 

§o! 

•S       i 

"S0  § 

&.g 
S'S 

v,  C 

I 

&o 

f,r 

t, 

&«! 

3  2  ^ 

£'.Q  >» 

% 
"3 

S 

<8 

• 

G 

• 
> 

g 

0^^ 

§§-§ 

S££ 

S  3 
»••& 

H  O'D 

I 

o 

fi 

P4"1 

X 

P-i 

•4 

m 

w 

m 

4 

CO 

CO 

Lbs. 

Lbs. 

Feet. 

Tons. 

Lbs. 

Lbs. 

op 

Lbs. 

Incli. 

Manufac- 

14 

D  i  a  m  o  n  d- 

50 

20.5 

169 

2,380 

435 

5.380 

80.9 

2,200 

24.9 

153 

(i) 

turers'. 

point  cut,  6 

to  the  inch. 

Do 

14 

..      do.... 

50 

20.5 

171 

2,400 

458 

G.  650 

68.9 

2  070 

24.9 

150 

(i) 

Do  

14 

do  

50 

20. 

171 

2,400 

430 

6.  850 

62.7 

2,  130 

24.  9 

145 

H 

Do  

14 

..      do... 

50 

20. 

171 

2,400 

416 

7.040 

69.  1 

24.9 

149 

m 

Do... 

14 

do.  .. 

50 

20. 

171 

2,400 

430 

6.  610 

65.  0 

24.9 

149 

Do.... 

14 

..      do.... 

50 

20. 

171 

2,400 

4  ''7 

7.  070 

60.4 

2,190 

25.8 

150 

(c) 

Do  

14 

do  

50 

20. 

171 

2,400 

447 

7.  550 

59.2 

25.  8 

150 

Do  

14 

..      do  

50 

20. 

171 

2,400 

df\C 

8.300 

55.3 

25.8 

147 

n 

Do  

14 

do  

50 

20. 

171 

2,400 

441 

7.700 

57.3 

2,190 

25.1 

147 

i 

Do  

14 

..      do  

50 

20. 

171 

2,400 

jor 

7.420 

58.0 

2,075 

25.  1 

151 

i) 

Do 

11 

do 

50 

20 

171 

2  400 

4^1 

4  960 

85  0 

2  025 

25  1 

154 

ll 

Do.  .   . 

14 

..      do  

50 

20. 

171 

2,400 

6.035 

76.0 

2,180 

25.  1 

162 

i) 

Do 

14 

50 

20 

171 

2  400 

446 

6  635 

67  3 

2  200 

25  1 

150 

Do...   . 

14 

.  do.... 

50 

20. 

2,400 

445 

7.  135 

62  5 

2,  190 

25.1 

147 

t< 

Do 

14 

do    .. 

50 

20 

171 

2,400 

462 

7  440 

62  2 

2  160 

25  4 

143 

j\ 

Do  

14 

..      do  

50 

20. 

171 

2,400 

6,860 

66.0 

2,153 

25.4 

14S 

(1) 

Do 

14 

do. 

50 

20. 

171 

2,400 

484 

7  560 

64  0 

2,155 

25  4 

142 

Do  

14 

do  

50 

20. 

171 

2,400 

467 

7.335 

63.7 

2,235 

25.4 

137 

0) 

Weighted  av- 

436 

7.030 

2.170 

148 

erages. 

Size  of  screen  slots,  0.065  and  0.012. 
SEASONED  MATERIAL. 


Manufac- 

14 

Diamond 

50 

20.5 

171 

2,400 

457 

5.140 

89.0 

2,125 

25.4 

147 

/0.065 
1      019 

turers'. 

point,  cut  6 

1    .  Ul^S 

to  the  inch. 

Do  

14 

do  

50 

20.5 

171 

2,400 

451 

5.570 

81.0 

2,170 

25.6 

142 

•'  .  065 
i   .012 

Do  

14 

do  

50 

20.5 

171 

2,400 

468 

6.780 

69.0 

2,210 

25.6 

140 



/  .065 
i  .012 

Do  

14 

do  

50 

20.5 

171 

2,400 

455 

7.050 

64.5 

2,260 

25.6 

136 

/  .065 
\  .012 

Do 

14 

do    . 

50 

20.5 

171 

2,400 

460 

7.  365 

62.4 

2,233 

25.6 

142 

.065 

.012 

Do  

14 

do.... 

50 

20.5 

171 

2,400 

490 

6.160 

79.5 

2,150 

25.6 

154 

.065 

.012 

Do  

14 

.      do  

50 

20.5 

171 

2,400 

3S6 

3.995 

96.6 

2,095 

25.6 

152 

.  065 

.012 

Do  

14 

do  

50 

20.5 

171 

2,400 

421 

6.240 

67.6 

2,225 

25.6 

144 

.065 
.012 

Do  

14 

do  

50 

20.5 

171 

2,400 

444 

6.340 

70.0 

2,320 

25.6 

152 

.065 
.012 

Do  

14 

do  

50 

20.5 

171 

2,400 

417 

5,990 

69.7 

25.6 

146 

.065 
\  .012 

Weighted'  av- 

447 

6.  2SO 

72.7 

2,210 

145 

erages. 

SEASONED  MATERIAL. 


Lombard  . 

24 

Straight  cut,  3 
to  the  inch; 

40 

16.4 

175 

2,445 

385 

4.190 

91.9 

2,220 

25.6 

169.4 

10.065 
\  .012 

spiral  cut,  12 
to  the  inch. 

{/u>e 

Do  

24 

do  

45 

IS.  46 

175 

2,445 

404 

4.  100 

91.8 

2,220 

25.6 

182.0 

.012 

Weighted  av- 

395 

4.  305 

91.  8 

2,220 

25.6 

176.3 

14.9 

erages. 

•T\OK    PINE   AND    HEMLOCK    FOR    MECHANICAL   PULP. 


27 


TABLE  7. — Quantitative  and  commercial  test  on  mixtures  of  spruw,  jack  pine,  and  hemlock — 
Power  consumption  and  production. 


^ 

. 

g 

0 

4 

.2 

4 

•3 

f 

i 

.a 

1 

4 

3 

a 

i 

Ig 

§^ 

I 

2 

Kind  of  stone. 

rcial  run  num 

Kind  of  burr. 

4 
g 

e  per  square 
pocket  area. 

tions  per  mini 

?ral  speed  per  i 

W   SH 
•p 

ry  pulp  in  24  1 

ower  per  ton 
pulp  in  24  hot 

ry  pulp  per  1(X 
bone-dry  woe 

per  cubic  fool 
dry  wood. 

II 

Qgs  per  100  cut 
bone-dry  wooc 

screen  slots. 

a 
a 

1 

I 

| 

i 

i 

s 

ra 

II 

o 

1*" 

i 

M 

O 
t> 

! 

"3 

3 

i! 

PH 

PS 

PH 

•< 

PQ 

n 

PQ 

F 

•J 

& 

w 

$  spruce;  §  hem- 
lock: 

Lbs. 

Lbs. 

Ft. 

Tows. 

Tb<t 

ibs 

°7T 

Lbs. 

In. 

Lombard 

46A 

/Straight  cut,  \  rft 
\  Stothainch.  1  Ol 

20.5 

175 

2,450 

392.0 

4.275 

91.7 

152.5 

(0.065 
\  .012 

Hemlock: 

Lombard 

46  B 

rln 

50 

20.5 

175 

2,450 

413.0 

4.885 

84.6 

175.5 

/  .065 
\  .012 

Spruce: 

Lombard  

46C 

do  

50 

20.5 

175 

2,450 

407.0 

4.878 

83.5 

160.0 

/  .065 
\  .012 

J  spruce;  §  hem- 

lock: 

Lombard  

49A 

Straight  cut, 
3  to  the  inch; 

40 

16.4 

175 

2,445 

360.4 

4.880 

73.8 

155.0 

/  .065 
\  .012 

spiral  cut,  12 

to  the  inch. 

Hemlock: 

Lombard 

49B 

do 

40 

16.4 

175 

2,445 

370.0 

4.885 

75.7 

168  3 

f  .065 
\.012 

COMMERCIAL  RUNS. 


§  spruce;  ^hem- 
lock: ' 

Lombard  
Do 

46A 
46A 

(Straight  cut, 
1  3  to  the  inch; 
|  spiral  cut,  12 
[  to  the  inch. 

do 

|, 

50 
50 

20.5 

20.5 
20.5 

175 

175 
175 

2,445 

2,445 
2,445 

426.0 

425.0 
432.0 

5.  660 

5.  135 
4.905 

75.3 

82.7 
88.0 





149.0 
173  0 

10.065 
\  .012 

/  .065 
\  .012 
(  .065 
\  .012 

-      .  —  T 

/  .065 
\  .012 

/  .065 
t  .012 

Do 

46A 

do 

176  3 

^  jack  pine;     § 
spruce;       | 
hemlock: 

Lombard  
Do  

51 
51 

Weighted 
averages. 

[Straight  cut, 
1  3  to  the  inch; 
|  spiral  cut,  12 
I  to  the  inch. 

do 

16.3 

t 

427.2 

"" 

442.0 
444.0 

5.175 

5.705 
5.420 

83.0 

77.5 
81.9 

2,030 

f24.  8  \ 
\23.  76f 

-  — 

169.0 
167.6 

/ 

175 
175 

2,445 
2,445 

I- 

50 

20.5 
20.5 





175.0 

i  jack  pine;     § 
hemlock: 

Lombard  
Do 

52 

52 
52 

Weighted 
averages. 

("Straight  cut, 
1  3  to  the  inch; 
|  spiral  cut,  12 
1.  to  the  inch, 
do 

\ 

443.0 

_     " 

398.0 

425.0 
406.5 

5.575 

-  '_. 

4.550 

4.350 
3.950 

79.4 

:== 

87.5 

97.7 
103.0 

2,232 

—  '_!-  

(25.  6  } 

i24-  7  t 
l29.ll) 

-..-..-  

171.0 
160.0 

17.4 



"  -^* 

f  .065 
\  .012 

/  .065 
\.012 
/  .065 
(.012 

} 



20.5 

20.5 
20.5 

175 

175 
175 

1" 

50 
50 

2,445 

2,445 
2,445 





185.4 
179  4 

.... 

Do  

do  

Weighted 
averages. 

17.6 

I 

414.0 

4.310 

96.3 

2,230 

f25.  2  \ 
\26.  75/ 

177.7 



/" 

28  JACK    PINE   AND    HEMLOCK   FOR    MECHANIC 

8. — Commercial  tests  on  hemlock — Power  consumptic         .7  prodi 


Kind  of  stone. 

Commercial  run  number. 

Kind  of  burr. 

Pressure  on  14-inch  cylinder. 

Pressure  per  square  inch, 
pocket  area. 

Revolutions  per  minute. 

Peripheral  speed  per  minute. 

Average  horsepower  to 
grinder. 

Bone-dry  pulp  in  24  hours. 

Horsepower  per  ton  bone- 
dry  pulp  in  24  hours. 

Bone-dry  pulp  per  100  cubic 
feet  bone-dry  wood. 

Weight  per  cubic  foot  bone- 
dry  wood. 

Average  temperature  of 
grinding. 

Screenings  per  100  cubic  feet 
bone-dry  wood. 

Size  of  screen  slots. 

Manufacturers'  .  . 
Do 

14 

14 

/Spiral  cut,  10 
\  to  the  inch. 

do 

Lbs. 
}50 

50 
50 

Lbs. 
20.5 

20.5 
20.5 

175 
175 
175 

Ft. 

2,435 

2,435 
2,435 

331.0 
356.0 
353.0 

Tons. 

2.855 

3.795 
3.425 

116.0 
94.0 
103.0 

Lbs. 
1,955 

2,030 
2,122 

Lbs. 
24.8 

24.8 
24.8 

°  F. 
173.5 

168.0 
173.0 

Lbs. 

.10.  C 

In. 
(0  065 
(  .C12 
1    .065 
1   .012 
/   .065 
\  .012 

Do 

14 

do     . 

Manufacturers'  .. 
Do 

M-l 

14-1 

Weighted 
averages. 

(Spiral  cut,  10 
\  to  the  inch. 

do 

349.0 

363.0 
371.5 

3.417 

103.1 

2,048 

i   - 

2,070 
2,080 

24.8 

171.4 

2,432 
2,432 

}50 

50 

20.5 
20.5 

175 
175 

4.195 
4.068 

86.5 
91.4 

24.8 
24.8 

165.5 
108.  0 

18.6 
18.5 

f   .065 
\  .012 
/  .065 
\  .012 

Manufacturers'... 
Do 

8 
8 

Weighted 
averages. 

{Straight  cut, 
10     to     the 
inch. 

do 

368.2 

4.115 

89.5 

87.7 

84.2 
97.5 

2,077 

24.8 

167.0 

165.5 

159.0 
177.6 

f  .065 
\  .012 

/  .065 
\  .012 
/  .065 
V  .012 

F 

40 
40 

16.4 

16.4 
16.4 

176 

176 
176 

2,450 

2,450 
2,450 

346.0 

287.0 
270.0 

306.0 

3.945 

3.410 
2.772 

2,118 

2,085 
2,038 

24.8 

24.8 
24.8 

24.8 

15.5 
18.6 

Do 

8 

do 

Manufacturers'.  .  . 
Do 

23 
?3 

Weighted 
averages. 

{Diamond 
point,  cut  10 
to  the  inch. 

do 

3.435 

89.7 

109.5 

87.5 
83.9 

2,083 



2,040 

2,125 
2,130 

24.8 

24.8 

24.8 
24.8 

168.4 

}. 

40 
40 

16.4 

16.4 
16.4 

176 

176 
176 

2,440 

2,440 
2,432 

300.0 

318.0 
281.0 

2.740 

3.635 
3.350 

186.5 

172.0 
162.0 

13.7 

32.7 
20.3 

/  .065 
\  .012 

f  .065 
\  .012 
f   .065 
\  .012 

Do 

?3 

do 

Lombard 

30 
"W 

Weighted 
averages. 

{Straight  cut, 
4  to  the  inch; 
spiral  cut,  10 
to  the  inch. 

do 

301.0 

3.300 

92.4 

2,105 

24.8 

172.8 

<   .065 
\  .012 

f  .065 
\  .012 

40 
40 

16.4 
16.4 

176 
176 

2,432 
2,432 

340.0 
315.0 

4.075 
3.  ,170 

83.5 
99.4 

2,080 
2,140 

24.8 

24.8 
24.8 

25.2 

25.2 
24.84 

176.0 
179.5 

16.5 

17.8 

Do 

Lombard 

50 
r.O 

Weighted 

averages. 

(Straight  cut, 
3  to  the  inch; 
spiral  cut,  12 
to  the  inch. 

do 

331.0 

417.0 

417.0 
422.5 

418.0 

3.725 

•_•-•-•• 

4.05 

3.815 
5.300 

89.5 

2,102 

177.0 

184.5 

185.0 
170.6 

175 

175 

175 

1" 

60 
50 

20.5 

20.5 
20.5 

2,445 

2,445 
2,445 

103.0 

109.2 
79.7 

2,195 

2,19£ 
2,070 

11.2 
11.2 

(  .065 
\  .012 

/  .065 
\  .012 
/  .065 
\  .012 

Do 

Do  

50 

do... 

Weighted 
averages. 

4.370 

97.5 

2,160 

25.1 

180.3 

.1ATK     PINE    AND    HEMLOCK    FOE 


A.L    PULP. 


TABLE  9. — Quantitative    and  commercial    tests   on   spruce — Power    consumption   and 

production. 


A 

g 

| 

% 

fc. 

c5 

a  a 

5<6 

£ 

3>- 

g 

C3     • 

a, 

& 

> 

3 

CM  3 

3 

-H^ 

+2 

S-S 

'I 

ftjg 

k 

a 

s$ 

wl? 

P  £ 

ll 

I 

i 

Kind  of 

stone. 

un  numbei 

Kind  of  burr. 

f 

If 

evolutions 
ute 

il 

|a 

ft 

i 

11 

if 

> 

|1 

i 

orsepower 
bone-dry 
24  hours. 

1! 

reight  per  c 
bone-dry 

G)  So 
C3  o 

P 

1!| 

g  0  > 

•5 

g 

PH 

PH 

PH 

PH 

PH 

•<! 

cq 

W 

PH 

P 

•^ 

CO 

CQ 

Lbs. 

Lbs. 

Ft. 

lows. 

L6s. 

Z6». 

•k 

Lfts. 

In. 

Lombard  .  . 

1 

Straight  cut, 

3  to  the  inch; 

40 

16.4 

2  445 

403 

4  988 

80.8 

171.0 

fO.065 

spiral  cut,  12 

50 

20.5 

\0.  012 

to  the  inch. 

Do 

do 

1      40 

16.4 

Il75 

2  445 

399 

4  525 

88  1 

175  5 

10.065 

\      50 

20.5 

f 

\0.  012 

Weigh  ted 

401 

4  810 

83  5 

2  480 

28  4 

172  6 

17  2 

averages. 

Do 

2 

Straight  cut, 

40 

16.4 

200 

2,795 

398 

4.245 

93.8 

164.3 

3  to  the  inch; 

spiralcut,  12 

to  the  inch. 

Do  

9. 

do  

40 

16.4 

200 

2,795 

408 

3.995 

102.0 

171.  S 

Do 

2 

do 

40 

16  4 

•>oo 

2  795 

394 

4  175 

94  4 

166  7 

Weigh  ted 

402 

4  120 

97  5 

2  012 

22  72 

168.0 

13  75 

averages. 

„ 

Straight  cut 

20 

8  2 

175 

2  445 

101 

1  215 

157.0 

2,300 

27.66 

163.0 

9.82 

3  to  the  inch; 

spiral  cut,  12 

to  the  inch. 

4 

do..  

40 

16.4 

175 

2,445 

333 

3.025 

110.0 

2,408 

27.66 

166.5 

17.8 

5 

....do. 

60 

24.65 

1  75 

2,  445 

454 

5.255 

86.4 

2,415 

27.66 

152.2 

18.6 

TABLE  10. — Furnish  to  beater  on  basis  of  1,000  pounds  of  stock — Experimental  and 

commercial  papers. 


EXPERIMENTAL  PAPER. 


1 

1 

•a 

a 

1 

PH 

<i 

1 

P 

ft 

0 

0 

S 

a 

ffi 

W) 

O 

3 

bo   . 

"d 

bo   . 

'rt  08 

s 

T3     . 

0 

O 

Run. 

X 

0)  O 

*P 

a  p 

C3§ 

3 

°d 

a 

tf 

% 

g 

3  ^ 

0  ^ 

ft^ 

T3  * 

.2 

S 

g 

bo 

a 

3 

a 

o> 

h 

a 

0 

S 

ti 
3 

jr 

0 

,a 

3 

03 

3 

P 

& 

w 

CO 

w 

CO 

^ 

o 

PH 

CO 

P 

O 

r,fc», 

'Lint. 

Lbs 

Lfefc 

Lbs 

Lbs. 

Lbs. 

02. 

0?, 

02. 

02. 

0^. 

Commercial  

1  A 

50 

950 

8 

8 

20 

0  067 

3.33 

Do 

250 

750 

8 

8 

20 

067 

3  33 

Do  

24 

750 

8 

8 

20 

3.6 

0.15 

Do 

46 

250 

250 

500 

8 

8 

20 

4  0 

15 

Do 

50 

250 

750 

8 

8 

20 

3  7 

20 

Do 

51 

250 

250 

250 

250 

8 

8 

20 

4  1 

15 

Do  

500 

250 

8 

8 

20 

4.3 

.15 

COMMERCIAL  PAPER. 


No  2  white  manila 

210 

395 

395 

8 

s 

2  8 

Butchers  manila  

<>10 

263 

527 

•>n 

^0 

26.7 

2.75 

0.83 

O 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 
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Return  to  desk  from  which  borrowed. 
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